diff --git a/include/emqttd_protocol.hrl b/include/emqttd_protocol.hrl
index a7eb768e3..6181b9a65 100644
--- a/include/emqttd_protocol.hrl
+++ b/include/emqttd_protocol.hrl
@@ -133,7 +133,7 @@
 %% Max MQTT Packet Length
 %%--------------------------------------------------------------------
 
--define(MAX_PACKET_LEN, 16#fffffff).
+-define(MAX_PACKET_SIZE, 16#fffffff).
 
 %%--------------------------------------------------------------------
 %% MQTT Parser and Serializer
diff --git a/src/emqttd_serializer.erl b/src/emqttd_serializer.erl
index f6d89cc60..a47a23c8b 100644
--- a/src/emqttd_serializer.erl
+++ b/src/emqttd_serializer.erl
@@ -42,7 +42,7 @@ serialize_header(#mqtt_packet_header{type   = Type,
                  {VariableBin, PayloadBin})
     when ?CONNECT =< Type andalso Type =< ?DISCONNECT ->
     Len = byte_size(VariableBin) + byte_size(PayloadBin),
-    true = (Len =< ?MAX_PACKET_LEN),
+    true = (Len =< ?MAX_PACKET_SIZE),
     [<<Type:4, (opt(Dup)):1, (opt(Qos)):2, (opt(Retain)):1>>,
      serialize_len(Len), VariableBin, PayloadBin].