diff --git a/trunk/src/app/srs_app_gb28181.cpp b/trunk/src/app/srs_app_gb28181.cpp
index ec0b7022b..6414999ae 100644
--- a/trunk/src/app/srs_app_gb28181.cpp
+++ b/trunk/src/app/srs_app_gb28181.cpp
@@ -1810,7 +1810,7 @@ void SrsGb28181RtmpMuxer::close()
     h264_pps = "";
     aac_specific_config = "";
 
-    if (source_publish && !source){
+    if (source_publish && NULL!=source){
         source->on_unpublish();
     }
 }
@@ -2400,4 +2400,4 @@ srs_error_t SrsGb28181Manger::query_sip_session(std::string id, SrsJsonArray* ar
     }
     
     return sip_service->query_sip_session(id, arr);
-}
\ No newline at end of file
+}