diff --git a/trunk/src/app/srs_app_forward.cpp b/trunk/src/app/srs_app_forward.cpp
index d64b02eae0..9cb69f8212 100755
--- a/trunk/src/app/srs_app_forward.cpp
+++ b/trunk/src/app/srs_app_forward.cpp
@@ -94,7 +94,7 @@ srs_error_t SrsForwarder::on_publish()
 void SrsForwarder::on_unpublish()
 {
     trd->stop();
-    sdk->close();
+    if (sdk) sdk->close();
 }
 
 srs_error_t SrsForwarder::on_meta_data(SrsSharedPtrMessage* shared_metadata)