diff --git a/src/emqtt_bench.erl b/src/emqtt_bench.erl
index e06fb9d..01b4fc0 100644
--- a/src/emqtt_bench.erl
+++ b/src/emqtt_bench.erl
@@ -645,18 +645,25 @@ loop(Parent, N, Client, PubSub, Opts) ->
 	end.
 
 put_publish_begin_time() ->
-    NowT = erlang:monotonic_time(millisecond),
-    put(last_publish_ts, NowT),
+    case get(last_publish_ts) of
+        undefined ->
+            NowT = erlang:monotonic_time(millisecond),
+            put(last_publish_ts, NowT);
+        _ ->
+            ok
+    end,
     ok.
 
 next_publish(Opts) ->
+    inc_counter(pub),
+    BeginTime = get(last_publish_ts),
+    PubCnt = get_counter(pub),
     Interval = proplists:get_value(interval_of_msg, Opts),
-    LastT = get(last_publish_ts),
+    NextTime = BeginTime + PubCnt * Interval,
     NowT = erlang:monotonic_time(millisecond),
-    Spent = NowT - LastT,
-    Remain = Interval - Spent,
+    Remain = NextTime - NowT,
     Interval > 0 andalso Remain < 0 andalso inc_counter(pub_overrun),
-    inc_counter(pub),
+
     case Remain > 0 of
         true -> _ = erlang:send_after(Remain, self(), publish);
         false -> self() ! publish