diff --git a/src/observer/main.cpp b/src/observer/main.cpp
index 23542dce4f..d230c07a69 100644
--- a/src/observer/main.cpp
+++ b/src/observer/main.cpp
@@ -399,7 +399,7 @@ static int check_uid_before_start(const char *dir_path)
 
 static void print_all_thread(const char* desc)
 {
-  MPRINT("============= [%s]begin to show unstopped thread =============", desc);
+  MPRINT("============= [%s] begin to show unstopped thread =============", desc);
   DIR *dir = opendir("/proc/self/task");
   if (dir == NULL) {
     MPRINT("fail to print all thread");
@@ -421,12 +421,12 @@ static void print_all_thread(const char* desc)
       if (len > 0 && name[len - 1] == '\n') {
         name[len - 1] = '\0';
       }
-      MPRINT("tid: %s, name: %s", tid, name);
+      MPRINT("[%s] detect unstopped thread, tid: %s, name: %s", desc, tid, name);
       fclose(file);
     }
   }
   closedir(dir);
-  MPRINT("============= [%s]finish to show unstopped thread =============", desc);
+  MPRINT("============= [%s] finish to show unstopped thread =============", desc);
 }
 
 extern "C" {