diff --git a/nbd/src/NBDTool.cpp b/nbd/src/NBDTool.cpp
index 14ffc7fb8e..8d69bd4a27 100644
--- a/nbd/src/NBDTool.cpp
+++ b/nbd/src/NBDTool.cpp
@@ -111,8 +111,26 @@ int NBDTool::Connect(NBDConfig *cfg) {
 }
 
 int NBDTool::Disconnect(const std::string& devpath) {
+    pid_t devpid = -1;
+    std::vector<DeviceInfo> devices;
+
+    int ret = List(&devices);
+    for (const auto& device : devices) {
+        if (device.config.devpath == devpath) {
+            devpid = device.pid;
+            break;
+        }
+    }
+
     NBDControllerPtr nbdCtrl = GetController(false);
-    return nbdCtrl->DisconnectByPath(devpath);
+    ret = nbdCtrl->DisconnectByPath(devpath);
+    if (ret != 0) {
+        return ret;
+    }
+
+    ret = WaitForTerminate(devpath, devpid, 5000);
+
+    return 0;
 }
 
 int NBDTool::List(std::vector<DeviceInfo>* infos) {
@@ -137,6 +155,8 @@ void NBDTool::RunServerUntilQuit() {
     } else {
         ctrl->RunUntilQuit();
     }
+
+    nbdWatchCtx_->StopWatch();
 }
 
 ImagePtr g_test_image = nullptr;
@@ -150,5 +170,31 @@ ImagePtr NBDTool::GenerateImage(const std::string& imageName) {
     return result;
 }
 
+int NBDTool::WaitForTerminate(const std::string& devpath, pid_t pid,
+                              uint64_t totalRetryMs) {
+    if (pid < 0) {
+        return 0;
+    }
+
+    // TODO(wuhanqing): make this to NBDConfig
+    int times = 20;
+    uint64_t sleepMs = totalRetryMs / times;
+
+    while (times-- > 0) {
+        if (kill(pid, 0) == -1) {
+            if (errno == ESRCH) {
+                return 0;
+            }
+            std::cerr << "curve-nbd test device failed, dev: " << devpath
+                      << ", err = " << cpp_strerror(-errno) << std::endl;
+            return -errno;
+        }
+
+        std::this_thread::sleep_for(std::chrono::milliseconds(sleepMs));
+    }
+
+    return -ETIMEDOUT;
+}
+
 }  // namespace nbd
 }  // namespace curve
diff --git a/nbd/src/NBDTool.h b/nbd/src/NBDTool.h
index 9769b8d4f4..a6f1390ef4 100644
--- a/nbd/src/NBDTool.h
+++ b/nbd/src/NBDTool.h
@@ -68,6 +68,10 @@ class NBDTool {
     // 生成image instance
     ImagePtr GenerateImage(const std::string& imageName);
 
+    // wait curve-nbd process to exit
+    int WaitForTerminate(const std::string& devpath, pid_t pid,
+                         uint64_t totalRetryMs);
+
  private:
     class NBDSocketPair {
      public:
diff --git a/robot/Resources/keywords/test_curve_stability_nbd.py b/robot/Resources/keywords/test_curve_stability_nbd.py
index bcb86ed6a6..e6ab1f52c5 100644
--- a/robot/Resources/keywords/test_curve_stability_nbd.py
+++ b/robot/Resources/keywords/test_curve_stability_nbd.py
@@ -705,6 +705,7 @@ def test_snapshot_all(vol_uuid):
     test_clone_iovol_consistency(lazy)
 #    test_clone_vol_same_uuid(lazy)
     test_recover_snapshot(lazy)
+    config.snapshot_thrash.nbd_unmap()
     config.snapshot_thrash.nbd_delete()
     return "finally"