diff --git a/client/lib/state/connection_provider.dart b/client/lib/state/connection_provider.dart
index 6362e8b..63118e2 100644
--- a/client/lib/state/connection_provider.dart
+++ b/client/lib/state/connection_provider.dart
@@ -7,6 +7,7 @@
 //   - 状态来源：bridge.statusStream（来自内核回调），非 Timer 模拟。
 import 'dart:async';
 
+import 'package:flutter/widgets.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 
 import '../bridge/log.dart';
@@ -93,6 +94,19 @@ class ConnectionController extends StateNotifier<ConnectionState> {
         unawaited(_disconnect());
       }
     });
+    // 生命周期闸:切后台停看门狗,回前台再开。原因:后台(尤其 Android Doze)会把 urltest
+    // 的主动探测限流 → urltest 停更、但 speed 帧仍在流 → 路径 A 误判「上游死」把正常隧道断掉
+    // (实测 Honor 后台 ~1min 必现:logcat「urltest stale 59s → upstream dead」)。后台无 UI 可
+    // 响应,停掉最稳;回前台基准由 _onStats 首帧/gap 重置。真·内核掉线(路径 A',事件驱动)不受影响。
+    _lifecycle = AppLifecycleListener(
+      onStateChange: (s) {
+        if (s == AppLifecycleState.resumed) {
+          if (state.phase == VpnPhase.on && _watchdog == null) _startWatchdog();
+        } else if (s == AppLifecycleState.paused || s == AppLifecycleState.hidden) {
+          _stopWatchdog();
+        }
+      },
+    );
   }
 
   final Ref _ref;
@@ -102,6 +116,7 @@ class ConnectionController extends StateNotifier<ConnectionState> {
   ProviderSubscription<AuthState>? _authSub;
   Timer? _elapsed;
   Timer? _watchdog;
+  AppLifecycleListener? _lifecycle;
   bool _probing = false;
   // 最近一次 urltest 成功(经 proxy 真实可达)的时刻;路径 A 用其陈旧度判上游死。
   DateTime? _lastUrltestOk;
@@ -381,6 +396,7 @@ class ConnectionController extends StateNotifier<ConnectionState> {
     _authSub?.close();
     _stopElapsed();
     _stopWatchdog();
+    _lifecycle?.dispose();
     _api?.dispose();
     super.dispose();
   }
diff --git a/client/test/unit/connection_watchdog_test.dart b/client/test/unit/connection_watchdog_test.dart
index 0cff43b..6157795 100644
--- a/client/test/unit/connection_watchdog_test.dart
+++ b/client/test/unit/connection_watchdog_test.dart
@@ -203,6 +203,36 @@ void main() {
     await tester.pump();
   });
 
+  testWidgets('切后台停看门狗:后台 urltest 停而 speed 在流,不误判断连', (tester) async {
+    final bridge = _FakeBridge();
+    var fake = DateTime(2026, 1, 1);
+    final c = makeContainer(bridge, now: () => fake); // 都 up,排除路径B
+    addTearDown(bridge.dispose);
+    addTearDown(c.dispose);
+    await tester.pumpWidget(UncontrolledProviderScope(container: c, child: const SizedBox()));
+    c.read(selectedNodeCodeProvider.notifier).select('HK');
+    await driveOn(tester, c, bridge);
+    bridge.emitStats(urltestFrame(20)); // lastOk=t0
+    await tester.pump();
+    // 切后台(须走合法生命周期序列 resumed→inactive→hidden→paused)。
+    tester.binding.handleAppLifecycleStateChanged(AppLifecycleState.inactive);
+    tester.binding.handleAppLifecycleStateChanged(AppLifecycleState.hidden);
+    tester.binding.handleAppLifecycleStateChanged(AppLifecycleState.paused);
+    await tester.pump();
+    // 复现 Android 后台:speed 帧继续(每 8s、statsLive),urltest 停,墙上时钟走 >45s。
+    // 看门狗若仍在跑会误判 path A 切到 JP;已停则不动。
+    for (var i = 0; i < 8; i++) {
+      fake = fake.add(const Duration(seconds: 8));
+      bridge.emitStats(speedOnlyFrame);
+      await tester.pump();
+      await tester.pump(const Duration(seconds: 15));
+    }
+    expect(c.read(selectedNodeCodeProvider), 'HK', reason: '后台看门狗已停,不应误判 path A 切节点');
+    expect(c.read(connectionProvider).phase, VpnPhase.on, reason: '隧道保持连接');
+    bridge.emit(VpnStatus.off); // 收尾
+    await tester.pump();
+  });
+
   testWidgets('节点健康 → 保持连接,不触发任何动作', (tester) async {
     final bridge = _FakeBridge();
     final c = makeContainer(bridge); // 都 up