diff --git a/apps/iot/src/iot_watchdog.erl b/apps/iot/src/iot_watchdog.erl
index 66112c9..1385a67 100644
--- a/apps/iot/src/iot_watchdog.erl
+++ b/apps/iot/src/iot_watchdog.erl
@@ -169,7 +169,7 @@ handle_info({timeout, _, warn_ticker}, State = #state{warn_buf = WarnBuf, url =
     case length(WarnBuf) > 0 of
         true ->
             Warn0 = hd(WarnBuf),
-            Warn = iolist_to_binary([Warn0, <<"(累计: ">>, integer_to_binary(length(WarnBuf)), <<")">>]),
+            Warn = iolist_to_binary([Warn0, <<"(累计: "/utf8>>, integer_to_binary(length(WarnBuf)), <<")">>]),
             Body = format_warn(Warn, Users, PriKey),
             case catch do_post(Url, Body) of
                 {ok, Resp} ->