diff --git a/apps/iot/src/mnesia/mnesia_data_importer.erl b/apps/iot/src/mnesia/mnesia_data_importer.erl
index 334e20d..235b6dd 100644
--- a/apps/iot/src/mnesia/mnesia_data_importer.erl
+++ b/apps/iot/src/mnesia/mnesia_data_importer.erl
@@ -14,8 +14,7 @@
 -export([import_endpoints/0]).
 
 import_endpoints() ->
-    zhongdian_mqtt_endpoint(),
-    ok.
+    zhongdian_mqtt_endpoint().
 
 zhongdian_mqtt_endpoint() ->
     Mapper0 = "fun(LocationCode, Fields, Timestamp) ->