diff --git a/board/TencentOS_tiny_EVB_G0/KEIL/mqtt_iot_explorer_e53_light/demo/mqtt_iot_explorer_e53_light.c b/board/TencentOS_tiny_EVB_G0/KEIL/mqtt_iot_explorer_e53_light/demo/mqtt_iot_explorer_e53_light.c
index 73a5c01b..8fc5b696 100644
--- a/board/TencentOS_tiny_EVB_G0/KEIL/mqtt_iot_explorer_e53_light/demo/mqtt_iot_explorer_e53_light.c
+++ b/board/TencentOS_tiny_EVB_G0/KEIL/mqtt_iot_explorer_e53_light/demo/mqtt_iot_explorer_e53_light.c
@@ -214,7 +214,7 @@ static void mqtt_demo_task(void)
         printf("module mqtt sub success\n");
     }
 
-    memset(report_topic_name, sizeof(report_topic_name), 0);
+    memset(report_topic_name, 0, sizeof(report_topic_name));
     size = snprintf(report_topic_name, TOPIC_NAME_MAX_SIZE, "$thing/up/property/%s/%s", product_id, device_name);
     if (size < 0 || size > sizeof(report_topic_name) - 1) {
         printf("pub topic content length not enough! content size:%d  buf size:%d", size, (int)sizeof(report_topic_name));