diff --git a/src/mqtt_client_wrapper.cpp b/src/mqtt_client_wrapper.cpp
index 00f2e04..86e3020 100644
--- a/src/mqtt_client_wrapper.cpp
+++ b/src/mqtt_client_wrapper.cpp
@@ -135,7 +135,7 @@ static void on_mqtt_message_received(const std::string &topic, const std::string
             // 发送应答
             if (mqtt_client)
             {
-                mqtt_client->publish(g_app_config.mqtt.topics.substream_down_ack, reply.dump());
+                mqtt_client->publish(g_app_config.mqtt.topics.video_down_ack, reply.dump());
                 LOG_INFO("[MQTT] Replied to video_down: " + reply.dump());
             }
         }