diff --git a/skynet-src/skynet_multicast.c b/skynet-src/skynet_multicast.c
index ba2b74bb..378138d6 100644
--- a/skynet-src/skynet_multicast.c
+++ b/skynet-src/skynet_multicast.c
@@ -231,5 +231,7 @@ skynet_multicast_cast(struct skynet_context * from, struct skynet_multicast_mess
 		}
 	}
 
-	skynet_multicast_copy(msg, -release);
+	if (release != 0) {
+		skynet_multicast_copy(msg, -release);
+	}
 }