diff --git a/src/actions/keys.ts b/src/actions/keys.ts
index db11e2308..d2ac784ac 100644
--- a/src/actions/keys.ts
+++ b/src/actions/keys.ts
@@ -343,6 +343,10 @@ export async function editKey(
       }
     }
 
+    // 仅当调用方显式携带 expiresAt 字段时才更新/清除该字段：
+    // - 避免像“仅修改限额”这类局部更新把 expiresAt 意外清空
+    const hasExpiresAtField = Object.hasOwn(data, "expiresAt");
+
     const validatedData = KeyFormSchema.parse(data);
 
     // 服务端验证：Key限额不能超过用户限额
@@ -417,9 +421,23 @@ export async function editKey(
 
     // 移除 providerGroup 子集校验（用户分组由 Key 分组自动计算）
 
-    // 转换 expiresAt: undefined → null（清除日期），string → Date（设置日期）
-    const expiresAt =
-      validatedData.expiresAt === undefined ? null : new Date(validatedData.expiresAt);
+    // 转换 expiresAt：
+    // - 未携带 expiresAt：不更新该字段
+    // - 携带 expiresAt 但为空：清除（永不过期）
+    // - 携带 expiresAt 且为字符串：设置为对应 Date
+    const expiresAt = hasExpiresAtField
+      ? validatedData.expiresAt === undefined
+        ? null
+        : new Date(validatedData.expiresAt)
+      : undefined;
+
+    if (expiresAt && Number.isNaN(expiresAt.getTime())) {
+      return {
+        ok: false,
+        error: tError("INVALID_FORMAT"),
+        errorCode: ERROR_CODES.INVALID_FORMAT,
+      };
+    }
 
     const isAdmin = session.user.role === "admin";
     const prevProviderGroup = normalizeProviderGroup(key.providerGroup);
@@ -428,7 +446,7 @@ export async function editKey(
 
     await updateKey(keyId, {
       name: validatedData.name,
-      expires_at: expiresAt,
+      ...(hasExpiresAtField ? { expires_at: expiresAt } : {}),
       can_login_web_ui: validatedData.canLoginWebUi,
       ...(data.isEnabled !== undefined ? { is_enabled: data.isEnabled } : {}),
       limit_5h_usd: validatedData.limit5hUsd,
diff --git a/src/lib/validation/schemas.ts b/src/lib/validation/schemas.ts
index 85f538629..406157740 100644
--- a/src/lib/validation/schemas.ts
+++ b/src/lib/validation/schemas.ts
@@ -199,8 +199,11 @@ export const UpdateUserSchema = z.object({
   isEnabled: z.boolean().optional(),
   expiresAt: z.preprocess(
     (val) => {
-      // null/undefined/空字符串 -> 视为未设置
-      if (val === null || val === undefined || val === "") return undefined;
+      // 更新语义：
+      // - undefined：不更新该字段
+      // - null/空字符串：显式清除过期时间（永不过期）
+      if (val === undefined) return undefined;
+      if (val === null || val === "") return null;
 
       // 已经是 Date 对象
       if (val instanceof Date) {
@@ -222,6 +225,7 @@ export const UpdateUserSchema = z.object({
     },
     z
       .date()
+      .nullable()
       .optional()
       .superRefine((date, ctx) => {
         if (!date) {
diff --git a/tests/unit/actions/keys-edit-key-expires-at-clear.test.ts b/tests/unit/actions/keys-edit-key-expires-at-clear.test.ts
new file mode 100644
index 000000000..9a71a34b1
--- /dev/null
+++ b/tests/unit/actions/keys-edit-key-expires-at-clear.test.ts
@@ -0,0 +1,146 @@
+import { beforeEach, describe, expect, test, vi } from "vitest";
+
+const getSessionMock = vi.fn();
+vi.mock("@/lib/auth", () => ({
+  getSession: getSessionMock,
+}));
+
+vi.mock("next/cache", () => ({
+  revalidatePath: vi.fn(),
+}));
+
+const getTranslationsMock = vi.fn(async () => (key: string) => key);
+vi.mock("next-intl/server", () => ({
+  getTranslations: getTranslationsMock,
+}));
+
+const findKeyByIdMock = vi.fn();
+const updateKeyMock = vi.fn();
+
+vi.mock("@/repository/key", () => ({
+  countActiveKeysByUser: vi.fn(async () => 1),
+  createKey: vi.fn(async () => ({})),
+  deleteKey: vi.fn(async () => true),
+  findActiveKeyByUserIdAndName: vi.fn(async () => null),
+  findKeyById: findKeyByIdMock,
+  findKeyList: vi.fn(async () => []),
+  findKeysWithStatistics: vi.fn(async () => []),
+  updateKey: updateKeyMock,
+}));
+
+const findUserByIdMock = vi.fn();
+vi.mock("@/repository/user", async (importOriginal) => {
+  const actual = await importOriginal<typeof import("@/repository/user")>();
+  return {
+    ...actual,
+    findUserById: findUserByIdMock,
+  };
+});
+
+describe("editKey: expiresAt 清除/不更新语义", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+    getSessionMock.mockResolvedValue({ user: { id: 1, role: "admin" } });
+
+    findKeyByIdMock.mockResolvedValue({
+      id: 1,
+      userId: 10,
+      key: "sk-test",
+      name: "k",
+      isEnabled: true,
+      expiresAt: new Date("2026-01-04T23:59:59.999Z"),
+      canLoginWebUi: true,
+      limit5hUsd: null,
+      limitDailyUsd: null,
+      dailyResetMode: "fixed",
+      dailyResetTime: "00:00",
+      limitWeeklyUsd: null,
+      limitMonthlyUsd: null,
+      limitTotalUsd: null,
+      limitConcurrentSessions: 0,
+      providerGroup: "default",
+      cacheTtlPreference: null,
+      createdAt: new Date(),
+      updatedAt: new Date(),
+      deletedAt: null,
+    });
+
+    findUserByIdMock.mockResolvedValue({
+      id: 10,
+      name: "u",
+      description: "",
+      role: "user",
+      rpm: null,
+      dailyQuota: null,
+      providerGroup: "default",
+      tags: [],
+      limit5hUsd: null,
+      dailyResetMode: "fixed",
+      dailyResetTime: "00:00",
+      limitWeeklyUsd: null,
+      limitMonthlyUsd: null,
+      limitTotalUsd: null,
+      limitConcurrentSessions: null,
+      isEnabled: true,
+      expiresAt: null,
+      allowedClients: [],
+      allowedModels: [],
+      createdAt: new Date(),
+      updatedAt: new Date(),
+      deletedAt: null,
+    });
+
+    updateKeyMock.mockResolvedValue({ id: 1 });
+  });
+
+  test("不携带 expiresAt 字段时不应更新 expires_at", async () => {
+    const { editKey } = await import("@/actions/keys");
+
+    const res = await editKey(1, { name: "k2" });
+
+    expect(res.ok).toBe(true);
+    expect(updateKeyMock).toHaveBeenCalledTimes(1);
+
+    const updatePayload = updateKeyMock.mock.calls[0]?.[1] as Record<string, unknown>;
+    expect(Object.hasOwn(updatePayload, "expires_at")).toBe(false);
+  });
+
+  test("携带 expiresAt=undefined 时应清除 expires_at（写入 null）", async () => {
+    const { editKey } = await import("@/actions/keys");
+
+    const res = await editKey(1, { name: "k2", expiresAt: undefined });
+
+    expect(res.ok).toBe(true);
+    expect(updateKeyMock).toHaveBeenCalledTimes(1);
+    expect(updateKeyMock).toHaveBeenCalledWith(
+      1,
+      expect.objectContaining({
+        expires_at: null,
+      })
+    );
+  });
+
+  test("携带 expiresAt=YYYY-MM-DD 时应写入对应 Date", async () => {
+    const { editKey } = await import("@/actions/keys");
+
+    const res = await editKey(1, { name: "k2", expiresAt: "2026-01-04" });
+
+    expect(res.ok).toBe(true);
+    expect(updateKeyMock).toHaveBeenCalledTimes(1);
+
+    const updatePayload = updateKeyMock.mock.calls[0]?.[1] as Record<string, unknown>;
+    expect(updatePayload.expires_at).toBeInstanceOf(Date);
+    expect(Number.isNaN((updatePayload.expires_at as Date).getTime())).toBe(false);
+  });
+
+  test("携带非法 expiresAt 字符串应返回 INVALID_FORMAT", async () => {
+    const { editKey } = await import("@/actions/keys");
+
+    const res = await editKey(1, { name: "k2", expiresAt: "not-a-date" });
+
+    expect(res.ok).toBe(false);
+    if (!res.ok) {
+      expect(res.errorCode).toBe("INVALID_FORMAT");
+    }
+  });
+});
diff --git a/tests/unit/actions/users-edit-user-expires-at-clear.test.ts b/tests/unit/actions/users-edit-user-expires-at-clear.test.ts
new file mode 100644
index 000000000..59688791b
--- /dev/null
+++ b/tests/unit/actions/users-edit-user-expires-at-clear.test.ts
@@ -0,0 +1,49 @@
+import { beforeEach, describe, expect, test, vi } from "vitest";
+
+const getSessionMock = vi.fn();
+vi.mock("@/lib/auth", () => ({
+  getSession: getSessionMock,
+}));
+
+vi.mock("next/cache", () => ({
+  revalidatePath: vi.fn(),
+}));
+
+const getTranslationsMock = vi.fn(async () => (key: string) => key);
+const getLocaleMock = vi.fn(async () => "en");
+vi.mock("next-intl/server", () => ({
+  getTranslations: getTranslationsMock,
+  getLocale: getLocaleMock,
+}));
+
+const updateUserMock = vi.fn();
+vi.mock("@/repository/user", async (importOriginal) => {
+  const actual = await importOriginal<typeof import("@/repository/user")>();
+  return {
+    ...actual,
+    updateUser: updateUserMock,
+  };
+});
+
+describe("editUser: expiresAt 清除应写入数据库更新", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+    getSessionMock.mockResolvedValue({ user: { id: 1, role: "admin" } });
+    updateUserMock.mockResolvedValue({ id: 123 });
+  });
+
+  test("传入 expiresAt=null 应调用 updateUser(..., { expiresAt: null })", async () => {
+    const { editUser } = await import("@/actions/users");
+
+    const res = await editUser(123, { expiresAt: null });
+
+    expect(res.ok).toBe(true);
+    expect(updateUserMock).toHaveBeenCalledTimes(1);
+    expect(updateUserMock).toHaveBeenCalledWith(
+      123,
+      expect.objectContaining({
+        expiresAt: null,
+      })
+    );
+  });
+});
diff --git a/tests/unit/dashboard/edit-key-form-expiry-clear-ui.test.tsx b/tests/unit/dashboard/edit-key-form-expiry-clear-ui.test.tsx
new file mode 100644
index 000000000..bea163770
--- /dev/null
+++ b/tests/unit/dashboard/edit-key-form-expiry-clear-ui.test.tsx
@@ -0,0 +1,137 @@
+/**
+ * @vitest-environment happy-dom
+ */
+
+import fs from "node:fs";
+import path from "node:path";
+import type { ReactNode } from "react";
+import { act } from "react";
+import { createRoot } from "react-dom/client";
+import { NextIntlClientProvider } from "next-intl";
+import { beforeEach, describe, expect, test, vi } from "vitest";
+import { Dialog } from "@/components/ui/dialog";
+import { EditKeyForm } from "@/app/[locale]/dashboard/_components/user/forms/edit-key-form";
+
+vi.mock("next/navigation", () => ({
+  useRouter: () => ({ refresh: vi.fn() }),
+}));
+
+const sonnerMocks = vi.hoisted(() => ({
+  toast: {
+    success: vi.fn(),
+    error: vi.fn(),
+  },
+}));
+vi.mock("sonner", () => sonnerMocks);
+
+const keysActionMocks = vi.hoisted(() => ({
+  editKey: vi.fn(async () => ({ ok: true })),
+}));
+vi.mock("@/actions/keys", () => keysActionMocks);
+
+const providersActionMocks = vi.hoisted(() => ({
+  getAvailableProviderGroups: vi.fn(async () => []),
+}));
+vi.mock("@/actions/providers", () => providersActionMocks);
+
+function loadMessages() {
+  const base = path.join(process.cwd(), "messages/en");
+  const read = (name: string) => JSON.parse(fs.readFileSync(path.join(base, name), "utf8"));
+
+  return {
+    common: read("common.json"),
+    errors: read("errors.json"),
+    quota: read("quota.json"),
+    ui: read("ui.json"),
+    dashboard: read("dashboard.json"),
+    forms: read("forms.json"),
+  };
+}
+
+function render(node: ReactNode) {
+  const container = document.createElement("div");
+  document.body.appendChild(container);
+  const root = createRoot(container);
+
+  act(() => {
+    root.render(node);
+  });
+
+  return {
+    container,
+    unmount: () => {
+      act(() => root.unmount());
+      container.remove();
+    },
+  };
+}
+
+function clickButtonByText(text: string) {
+  const buttons = Array.from(document.body.querySelectorAll("button"));
+  const btn = buttons.find((b) => (b.textContent || "").includes(text));
+  if (!btn) {
+    throw new Error(`未找到按钮: ${text}`);
+  }
+  btn.dispatchEvent(new MouseEvent("click", { bubbles: true }));
+}
+
+describe("EditKeyForm: 清除 expiresAt 后应携带 expiresAt 字段提交（用于触发后端清除）", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  test("点击 Clear Date 后提交应调用 editKey 并携带 expiresAt 字段", async () => {
+    const messages = loadMessages();
+
+    const { unmount } = render(
+      <NextIntlClientProvider locale="en" messages={messages} timeZone="UTC">
+        <Dialog open onOpenChange={() => {}}>
+          <EditKeyForm
+            keyData={{ id: 1, name: "k", expiresAt: "2026-01-04T23:59:59.999Z" }}
+            user={{
+              id: 10,
+              name: "u",
+              description: "",
+              role: "user",
+              rpm: null,
+              dailyQuota: null,
+              providerGroup: "default",
+              tags: [],
+              dailyResetMode: "fixed",
+              dailyResetTime: "00:00",
+              isEnabled: true,
+              expiresAt: null,
+              createdAt: new Date(),
+              updatedAt: new Date(),
+            }}
+            isAdmin
+          />
+        </Dialog>
+      </NextIntlClientProvider>
+    );
+
+    await act(async () => {
+      clickButtonByText("2026-01-04");
+    });
+
+    await act(async () => {
+      clickButtonByText("Clear Date");
+    });
+
+    const submit = document.body.querySelector('button[type="submit"]') as HTMLButtonElement | null;
+    expect(submit).toBeTruthy();
+
+    await act(async () => {
+      submit?.dispatchEvent(new MouseEvent("click", { bubbles: true }));
+      await new Promise((r) => setTimeout(r, 0));
+    });
+
+    expect(keysActionMocks.editKey).toHaveBeenCalledTimes(1);
+    const [, payload] = keysActionMocks.editKey.mock.calls[0] as [number, any];
+
+    // 关键点：必须显式携带 expiresAt 字段（即使为 undefined），后端才会识别为“清除”
+    expect(Object.hasOwn(payload, "expiresAt")).toBe(true);
+
+    unmount();
+  });
+});
diff --git a/tests/unit/dashboard/user-form-expiry-clear-ui.test.tsx b/tests/unit/dashboard/user-form-expiry-clear-ui.test.tsx
new file mode 100644
index 000000000..9e50f7b77
--- /dev/null
+++ b/tests/unit/dashboard/user-form-expiry-clear-ui.test.tsx
@@ -0,0 +1,121 @@
+/**
+ * @vitest-environment happy-dom
+ */
+
+import fs from "node:fs";
+import path from "node:path";
+import type { ReactNode } from "react";
+import { act } from "react";
+import { createRoot } from "react-dom/client";
+import { NextIntlClientProvider } from "next-intl";
+import { beforeEach, describe, expect, test, vi } from "vitest";
+import { Dialog } from "@/components/ui/dialog";
+import { UserForm } from "@/app/[locale]/dashboard/_components/user/forms/user-form";
+
+vi.mock("next/navigation", () => ({
+  useRouter: () => ({ refresh: vi.fn() }),
+}));
+
+const sonnerMocks = vi.hoisted(() => ({
+  toast: {
+    success: vi.fn(),
+    error: vi.fn(),
+  },
+}));
+vi.mock("sonner", () => sonnerMocks);
+
+const usersActionMocks = vi.hoisted(() => ({
+  editUser: vi.fn(async () => ({ ok: true })),
+  addUser: vi.fn(async () => ({ ok: true, data: { user: { id: 1 } } })),
+}));
+vi.mock("@/actions/users", () => usersActionMocks);
+
+const providersActionMocks = vi.hoisted(() => ({
+  getAvailableProviderGroups: vi.fn(async () => []),
+}));
+vi.mock("@/actions/providers", () => providersActionMocks);
+
+function loadMessages() {
+  const base = path.join(process.cwd(), "messages/en");
+  const read = (name: string) => JSON.parse(fs.readFileSync(path.join(base, name), "utf8"));
+
+  return {
+    common: read("common.json"),
+    errors: read("errors.json"),
+    notifications: read("notifications.json"),
+    ui: read("ui.json"),
+    dashboard: read("dashboard.json"),
+    forms: read("forms.json"),
+  };
+}
+
+function render(node: ReactNode) {
+  const container = document.createElement("div");
+  document.body.appendChild(container);
+  const root = createRoot(container);
+
+  act(() => {
+    root.render(node);
+  });
+
+  return {
+    container,
+    unmount: () => {
+      act(() => root.unmount());
+      container.remove();
+    },
+  };
+}
+
+function clickButtonByText(text: string) {
+  const buttons = Array.from(document.body.querySelectorAll("button"));
+  const btn = buttons.find((b) => (b.textContent || "").includes(text));
+  if (!btn) {
+    throw new Error(`未找到按钮: ${text}`);
+  }
+  btn.dispatchEvent(new MouseEvent("click", { bubbles: true }));
+}
+
+describe("UserForm: 清除 expiresAt 后应提交 null", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  test("编辑模式：点击 Clear Date 后提交应调用 editUser(..., { expiresAt: null })", async () => {
+    const messages = loadMessages();
+    const expiresAt = new Date("2026-01-04T23:59:59.999Z");
+
+    const { unmount } = render(
+      <NextIntlClientProvider locale="en" messages={messages} timeZone="UTC">
+        <Dialog open onOpenChange={() => {}}>
+          <UserForm
+            user={{ id: 123, name: "u", rpm: null, dailyQuota: null, expiresAt }}
+            currentUser={{ role: "admin" }}
+          />
+        </Dialog>
+      </NextIntlClientProvider>
+    );
+
+    await act(async () => {
+      clickButtonByText("2026-01-04");
+    });
+
+    await act(async () => {
+      clickButtonByText("Clear Date");
+    });
+
+    const submit = document.body.querySelector('button[type="submit"]') as HTMLButtonElement | null;
+    expect(submit).toBeTruthy();
+
+    await act(async () => {
+      submit?.dispatchEvent(new MouseEvent("click", { bubbles: true }));
+      await new Promise((r) => setTimeout(r, 0));
+    });
+
+    expect(usersActionMocks.editUser).toHaveBeenCalledTimes(1);
+    const [, payload] = usersActionMocks.editUser.mock.calls[0] as [number, any];
+    expect(payload.expiresAt).toBeNull();
+
+    unmount();
+  });
+});
diff --git a/tests/unit/validation/user-schemas-expires-at-clear.test.ts b/tests/unit/validation/user-schemas-expires-at-clear.test.ts
new file mode 100644
index 000000000..a99360b5e
--- /dev/null
+++ b/tests/unit/validation/user-schemas-expires-at-clear.test.ts
@@ -0,0 +1,94 @@
+import { describe, expect, test } from "vitest";
+import { CreateUserSchema, UpdateUserSchema } from "@/lib/validation/schemas";
+
+describe("UpdateUserSchema: expiresAt 清除语义", () => {
+  test("expiresAt=null 应解析为 null（显式清除）", () => {
+    const parsed = UpdateUserSchema.parse({ expiresAt: null });
+    expect(parsed.expiresAt).toBeNull();
+  });
+
+  test("expiresAt='' 应解析为 null（显式清除）", () => {
+    const parsed = UpdateUserSchema.parse({ expiresAt: "" });
+    expect(parsed.expiresAt).toBeNull();
+  });
+
+  test("expiresAt 缺省应保持 undefined（不更新字段）", () => {
+    const parsed = UpdateUserSchema.parse({});
+    expect(parsed.expiresAt).toBeUndefined();
+  });
+
+  test("expiresAt=ISO 字符串应解析为 Date", () => {
+    const parsed = UpdateUserSchema.parse({ expiresAt: "2026-01-04T23:59:59.999Z" });
+    expect(parsed.expiresAt).toBeInstanceOf(Date);
+  });
+
+  test("expiresAt=非法字符串应校验失败", () => {
+    const result = UpdateUserSchema.safeParse({ expiresAt: "not-a-date" });
+    expect(result.success).toBe(false);
+  });
+
+  test("expiresAt=非法 Date 应校验失败", () => {
+    const bad = new Date("not-a-date");
+    const result = UpdateUserSchema.safeParse({ expiresAt: bad });
+    expect(result.success).toBe(false);
+  });
+
+  test("expiresAt=非字符串/非 Date 类型应校验失败", () => {
+    const result = UpdateUserSchema.safeParse({ expiresAt: 123 });
+    expect(result.success).toBe(false);
+  });
+
+  test("expiresAt 超过 10 年应被拒绝", () => {
+    const tooFar = new Date();
+    tooFar.setFullYear(tooFar.getFullYear() + 11);
+
+    const result = UpdateUserSchema.safeParse({ expiresAt: tooFar });
+    expect(result.success).toBe(false);
+  });
+});
+
+describe("CreateUserSchema: expiresAt 兼容性", () => {
+  test("CreateUserSchema 仍将 expiresAt=null 视为未设置", () => {
+    const parsed = CreateUserSchema.parse({ name: "test-user", expiresAt: null });
+    expect(parsed.expiresAt).toBeUndefined();
+  });
+
+  test("CreateUserSchema 支持 expiresAt=Date（未来时间）", () => {
+    const future = new Date();
+    future.setDate(future.getDate() + 1);
+    const parsed = CreateUserSchema.parse({ name: "test-user", expiresAt: future });
+    expect(parsed.expiresAt).toBeInstanceOf(Date);
+  });
+
+  test("CreateUserSchema 支持 expiresAt=ISO 字符串（未来时间）", () => {
+    const future = new Date();
+    future.setDate(future.getDate() + 1);
+    const parsed = CreateUserSchema.parse({ name: "test-user", expiresAt: future.toISOString() });
+    expect(parsed.expiresAt).toBeInstanceOf(Date);
+  });
+
+  test("CreateUserSchema: expiresAt=过去时间应被拒绝", () => {
+    const past = new Date();
+    past.setDate(past.getDate() - 1);
+    const result = CreateUserSchema.safeParse({ name: "test-user", expiresAt: past });
+    expect(result.success).toBe(false);
+  });
+
+  test("CreateUserSchema: expiresAt 超过 10 年应被拒绝", () => {
+    const farFuture = new Date();
+    farFuture.setFullYear(farFuture.getFullYear() + 11);
+    const result = CreateUserSchema.safeParse({ name: "test-user", expiresAt: farFuture });
+    expect(result.success).toBe(false);
+  });
+
+  test("CreateUserSchema: expiresAt=非法 Date 应校验失败", () => {
+    const bad = new Date("not-a-date");
+    const result = CreateUserSchema.safeParse({ name: "test-user", expiresAt: bad });
+    expect(result.success).toBe(false);
+  });
+
+  test("CreateUserSchema: expiresAt=非法字符串应校验失败", () => {
+    const result = CreateUserSchema.safeParse({ name: "test-user", expiresAt: "not-a-date" });
+    expect(result.success).toBe(false);
+  });
+});