diff --git a/src/mqtt_client_wrapper.cpp b/src/mqtt_client_wrapper.cpp
index 117d2be..8adc0b0 100644
--- a/src/mqtt_client_wrapper.cpp
+++ b/src/mqtt_client_wrapper.cpp
@@ -40,6 +40,8 @@ static void on_mqtt_message_received(const std::string &topic, const std::string
             }
 
             int status = j["data"]["status"].get<int>();
+            std::string seqNo = j["seqNo"].get<std::string>();
+            bool success = true; // 标记是否操作成功
 
             if (status == 0)
             {
@@ -74,7 +76,25 @@ static void on_mqtt_message_received(const std::string &topic, const std::string
             else
             {
                 LOG_WARN("[MQTT] video_down: unknown status value " + std::to_string(status));
+                success = false;
             }
+
+            // 获取当前时间 yyyyMMddHHmmssSSS
+            auto now = std::chrono::system_clock::now();
+            auto millis = std::chrono::duration_cast<std::chrono::milliseconds>(now.time_since_epoch()) % 1000;
+            std::time_t t = std::chrono::system_clock::to_time_t(now);
+            std::tm tm_now = *std::localtime(&t);
+            std::ostringstream time_ss;
+            time_ss << std::put_time(&tm_now, "%Y%m%d%H%M%S") << std::setw(3) << std::setfill('0') << millis.count();
+
+            nlohmann::json reply;
+            reply["time"] = time_ss.str();
+            reply["result"] = success ? 0 : 1;
+            reply["seqNo"] = seqNo;
+
+            // 发送应答
+            MQTTClientWrapper::publish(g_app_config.mqtt.topics.substream_down_ack, reply.dump());
+            LOG_INFO("[MQTT] Replied to video_down: " + reply.dump());
         }
         else if (topic == g_app_config.mqtt.topics.substream_down)
         {