diff --git a/example/lib/main.dart b/example/lib/main.dart
index b7b8677..fd0d563 100644
--- a/example/lib/main.dart
+++ b/example/lib/main.dart
@@ -5,6 +5,7 @@ import 'package:ble_ex_example/samples/cases/bleex_communication_case.dart';
 import 'package:ble_ex_example/samples/cases/bleex_reqeust_case.dart';
 import 'package:ble_ex_example/samples/cases/connect_by_dist_case.dart';
 import 'package:ble_ex_example/samples/cases/reconnect_case.dart';
+import 'package:ble_ex_example/samples/cases/scan_case.dart';
 import 'package:ble_ex_example/samples/cases/verify_central_case.dart';
 import 'package:flutter/material.dart';
 
@@ -20,11 +21,12 @@ void main() async {
 void runSampleCase(BleManager bleManager) {
   bleLog(tag, "Creating sample case");
   // CaseBase sampleCase = VerifyCentralCase();
-  CaseBase sampleCase = ReconnectCase();
+  // CaseBase sampleCase = ReconnectCase();
   // CaseBase sampleCase = BleCommunicationCase();
   // CaseBase sampleCase = BleexRequestCase();
   // CaseBase sampleCase = BleexCommunicationCase();
   // CaseBase sampleCase = ConnectByDistCase();
+  CaseBase sampleCase = ScanCase();
 
   sampleCase.init(bleManager);
   bleLog(tag, "Sample case created");
diff --git a/example/lib/samples/cases/scan_case.dart b/example/lib/samples/cases/scan_case.dart
new file mode 100644
index 0000000..d4b7d44
--- /dev/null
+++ b/example/lib/samples/cases/scan_case.dart
@@ -0,0 +1,18 @@
+import 'package:ble_ex/ble_ex.dart';
+import 'package:ble_ex_example/samples/cases/base_case.dart';
+import 'package:flutter_reactive_ble/flutter_reactive_ble.dart';
+
+class ScanCase extends CaseBase {
+  static const String tag = "ScanCase";
+
+  @override
+  Future<void> start() async {
+    bleManager.listenScanAddDevice(deviceScanHandler);
+    bleManager.listenScanUpdateDevice(deviceScanHandler);
+    bleManager.scanDevices();
+  }
+
+  void deviceScanHandler(DiscoveredDevice device) {
+    bleLog(tag, '$device');
+  }
+}
diff --git a/example/pubspec.lock b/example/pubspec.lock
index e317038..f040a5a 100644
--- a/example/pubspec.lock
+++ b/example/pubspec.lock
@@ -14,7 +14,7 @@ packages:
       path: ".."
       relative: true
     source: path
-    version: "0.9.2"
+    version: "0.9.3"
   boolean_selector:
     dependency: transitive
     description:
diff --git a/lib/src/ble_manager.dart b/lib/src/ble_manager.dart
index e26f106..a42d92f 100644
--- a/lib/src/ble_manager.dart
+++ b/lib/src/ble_manager.dart
@@ -68,6 +68,7 @@ class BleManager extends Object {
   Uint8List? _manufacturerFilter;
 
   void scanDevices({Uint8List? manufacturerFilter}) async {
+    await stopScanDevices();
     _doScanDevices(true, manufacturerFilter: manufacturerFilter);
   }
 
@@ -163,7 +164,7 @@ class BleManager extends Object {
     _updateDeviceMap[device.id] = device;
   }
 
-  void stopScanDevices() {
+  Future<void> stopScanDevices() async {
     fireScanEvent = false;
     _targetServiceUuid = null;
     _targetManufacturerData = null;
@@ -177,14 +178,18 @@ class BleManager extends Object {
 
     if (_statusIniter != null) {
       _statusIniter!.cancel();
+      _statusIniter = null;
     }
     _statusIniter = null;
     if (_scanTimer != null) {
       _scanTimer!.cancel();
+      _scanTimer = null;
     }
     _scanTimer = null;
     if (_subscription != null) {
-      _subscription!.cancel();
+      await _subscription!.cancel();
+      _subscription = null;
+      await Future.delayed(const Duration(milliseconds: 200));
     }
   }
 
@@ -289,14 +294,14 @@ class BleManager extends Object {
 
   /// 得到目标蓝牙服务
   Future<DiscoveredDevice> scanForDevice(Uuid serviceUuid,
-      {Uint8List? manufacturerFilter}) {
-    stopScanDevices();
+      {Uint8List? manufacturerFilter}) async {
+    await stopScanDevices();
     fireScanEvent = false;
     Completer<DiscoveredDevice> _completer = Completer();
     _targetServiceUuid = serviceUuid;
     _targetManufacturerData = manufacturerFilter;
-    _findTargetDeviceFunc = (device) {
-      stopScanDevices();
+    _findTargetDeviceFunc = (device) async {
+      await stopScanDevices();
       _completer.complete(device);
     };
     _doScanDevices(false);
diff --git a/pubspec.yaml b/pubspec.yaml
index c6499ff..f5552c0 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,6 +1,6 @@
 name: ble_ex
 description: A Flutter library based on flutter_reactive_ble. Added more operations for BLE communication.
-version: 0.9.2
+version: 0.9.3
 homepage: https://github.com/featherJ/ble_ex
 
 environment: