diff --git a/apps/emqx/src/emqx_zone_schema.erl b/apps/emqx/src/emqx_zone_schema.erl
index 5d6720986..ffa64572e 100644
--- a/apps/emqx/src/emqx_zone_schema.erl
+++ b/apps/emqx/src/emqx_zone_schema.erl
@@ -61,6 +61,9 @@ hidden() ->
         "flapping_detect"
     ].
 
+%% optimized for mqtt field
+fields("mqtt") ->
+    emqx_schema:fields("mqtt");
 %% zone schemas are clones from the same name from root level
 %% only not allowed to have default values.
 fields(Name) ->