diff --git a/src/mqtt_client_wrapper.cpp b/src/mqtt_client_wrapper.cpp
index d685a86..319490d 100644
--- a/src/mqtt_client_wrapper.cpp
+++ b/src/mqtt_client_wrapper.cpp
@@ -9,9 +9,6 @@ extern std::atomic<bool> g_running;
 std::string g_dispatch_id;
 std::mutex g_dispatch_id_mutex;
 
-auto last_heartbeat = std::chrono::steady_clock::now();
-auto heartbeat_interval = std::chrono::milliseconds(static_cast<int>(g_app_config.mqtt.keep_alive * 0.9));
-
 static void send_heartbeat()
 {
     if (!mqtt_client || !mqtt_client->isConnected())
@@ -29,14 +26,9 @@ static void send_heartbeat()
     }
 
     nlohmann::json hb_data;
-    hb_data["time"] = Logger::get_current_time_utc8();
-
-    {
-        std::lock_guard<std::mutex> lock(g_dispatch_id_mutex);
-        if (!g_dispatch_id.empty())
-            hb_data["dispatchId"] = g_dispatch_id;
-    }
-
+    hb_data["time"] = Logger::get_current_time_utc8(); // UTC+8
+    if (!g_dispatch_id.empty())
+        hb_data["dispatchId"] = g_dispatch_id;
     hb_data["status"] = status;
 
     nlohmann::json msg;
@@ -209,6 +201,7 @@ static void on_mqtt_message_received(const std::string &topic, const std::string
 void mqtt_client_thread_func()
 {
     const auto &cfg = g_app_config.mqtt;
+    auto heartbeat_interval = std::chrono::milliseconds(static_cast<int>(cfg.mqtt.keep_alive * 0.9));
 
     while (g_running)
     {
@@ -222,20 +215,18 @@ void mqtt_client_thread_func()
         while (!mqtt_restart_required && g_running)
         {
             auto now = std::chrono::steady_clock::now();
-            if (now - last_heartbeat >= heartbeat_interval)
-            {
-                try
-                {
-                    send_heartbeat();
-                }
-                catch (const std::exception &e)
-                {
-                    LOG_ERROR(std::string("[MQTT] Heartbeat error: ") + e.what());
-                }
-                last_heartbeat = now;
-            }
 
-            std::this_thread::sleep_for(std::chrono::milliseconds(50)); // 轻量轮询
+            try
+            {
+                send_heartbeat();
+            }
+            catch (const std::exception &e)
+            {
+                LOG_ERROR(std::string("[MQTT] Heartbeat error: ") + e.what());
+            }
+            last_heartbeat = now;
+
+            std::this_thread::sleep_for(heartbeat_interval); // 固定周期
         }
 
         // 需要重启或退出