diff --git a/.changeset/popular-bees-invent.md b/.changeset/popular-bees-invent.md
new file mode 100644
index 000000000..47cf42798
--- /dev/null
+++ b/.changeset/popular-bees-invent.md
@@ -0,0 +1,5 @@
+---
+"@alauda/ui": patch
+---
+
+instanceof observable always fail
diff --git a/src/dialog/confirm-dialog/confirm-dialog.component.ts b/src/dialog/confirm-dialog/confirm-dialog.component.ts
index bba77a298..4e9dc5f49 100644
--- a/src/dialog/confirm-dialog/confirm-dialog.component.ts
+++ b/src/dialog/confirm-dialog/confirm-dialog.component.ts
@@ -10,7 +10,7 @@ import {
   Component,
   ViewEncapsulation,
 } from '@angular/core';
-import { firstValueFrom, Observable } from 'rxjs';
+import { firstValueFrom, isObservable } from 'rxjs';
 
 import { ButtonComponent } from '../../button/button.component';
 import { IconComponent } from '../../icon/icon.component';
@@ -113,7 +113,7 @@ export class ConfirmDialogComponent<T = unknown, R = unknown> {
 
     const result = (beforeAction as CustomBeforeAction<T>)();
 
-    if (result instanceof Observable) {
+    if (isObservable(result)) {
       return firstValueFrom(result);
     }