diff --git a/src/emqx_mqtt_caps.erl b/src/emqx_mqtt_caps.erl
index fdc29fae8..b8b7a5b3a 100644
--- a/src/emqx_mqtt_caps.erl
+++ b/src/emqx_mqtt_caps.erl
@@ -43,7 +43,9 @@
                        {mqtt_wildcard_subscription, true}]).
 
 -define(PUBCAP_KEYS, [max_qos_allowed,
-                      mqtt_retain_available]).
+                      mqtt_retain_available,
+                      mqtt_topic_alias
+                     ]).
 -define(SUBCAP_KEYS, [max_qos_allowed,
                       max_topic_levels,
                       mqtt_shared_subscription,
@@ -60,8 +62,15 @@ do_check_pub(Props = #{qos := QoS}, [{max_qos_allowed, MaxQoS}|Caps]) ->
         true  -> {error, ?RC_QOS_NOT_SUPPORTED};
         false -> do_check_pub(Props, Caps)
     end;
+do_check_pub(Props = #{ topic_alias := TopicAlias}, [{max_topic_alias, MaxTopicAlias}| Caps]) ->
+    case TopicAlias =< MaxTopicAlias andalso TopicAlias > 0 of
+        false -> {error, ?RC_TOPIC_ALIAS_INVALID};
+        true -> do_check_pub(Props, Caps)
+    end;
 do_check_pub(#{retain := true}, [{mqtt_retain_available, false}|_Caps]) ->
     {error, ?RC_RETAIN_NOT_SUPPORTED};
+do_check_pub(Props, [{max_topic_alias, _} | Caps]) ->
+    do_check_pub(Props, Caps);
 do_check_pub(Props, [{mqtt_retain_available, _}|Caps]) ->
     do_check_pub(Props, Caps).
 
@@ -136,4 +145,3 @@ with_env(Zone, Key, InitFun) ->
                      Caps;
         ZoneCaps  -> ZoneCaps
     end.
-
diff --git a/src/emqx_packet.erl b/src/emqx_packet.erl
index 715526964..fc90cf492 100644
--- a/src/emqx_packet.erl
+++ b/src/emqx_packet.erl
@@ -72,9 +72,11 @@ validate_packet_id(_) ->
 validate_properties(?SUBSCRIBE, #{'Subscription-Identifier' := I})
     when I =< 0; I >= 16#FFFFFFF ->
     error(subscription_identifier_invalid);
-validate_properties(?PUBLISH, # {'Topic-Alias':= I})
+validate_properties(?PUBLISH, #{'Topic-Alias':= I})
     when I =:= 0 ->
     error(topic_alias_invalid);
+validate_properties(?PUBLISH, #{'Subscription-Identifier' := _I}) ->
+    error(protocol_error);
 validate_properties(_, _) ->
     true.
 
@@ -236,4 +238,3 @@ format_password(_Password) -> '******'.
 i(true)  -> 1;
 i(false) -> 0;
 i(I) when is_integer(I) -> I.
-
diff --git a/src/emqx_protocol.erl b/src/emqx_protocol.erl
index 39929513e..7e95a4d90 100644
--- a/src/emqx_protocol.erl
+++ b/src/emqx_protocol.erl
@@ -33,36 +33,36 @@
 -export([shutdown/2]).
 
 -record(pstate, {
-          zone,
-          sendfun,
-          peername,
-          peercert,
-          proto_ver,
-          proto_name,
-          ackprops,
-          client_id,
-          is_assigned,
-          conn_pid,
-          conn_props,
-          ack_props,
-          username,
-          session,
-          clean_start,
-          topic_aliases,
-          packet_size,
-          will_topic,
-          will_msg,
-          keepalive,
-          mountpoint,
-          is_super,
-          is_bridge,
-          enable_ban,
-          enable_acl,
-          recv_stats,
-          send_stats,
-          connected,
-          connected_at
-         }).
+         zone,
+         sendfun,
+         peername,
+         peercert,
+         proto_ver,
+         proto_name,
+         ackprops,
+         client_id,
+         is_assigned,
+         conn_pid,
+         conn_props,
+         ack_props,
+         username,
+         session,
+         clean_start,
+         topic_aliases,
+         packet_size,
+         will_topic,
+         will_msg,
+         keepalive,
+         mountpoint,
+         is_super,
+         is_bridge,
+         enable_ban,
+         enable_acl,
+         recv_stats,
+         send_stats,
+         connected,
+         connected_at
+        }).
 
 -type(state() :: #pstate{}).
 -export_type([state/0]).
@@ -315,9 +315,12 @@ process_packet(Packet = ?PUBLISH_PACKET(?QOS_0, Topic, _PacketId, _Payload), PSt
     case check_publish(Packet, PState) of
         {ok, PState1} ->
             do_publish(Packet, PState1);
+        {error, ?RC_TOPIC_ALIAS_INVALID} ->
+            ?LOG(error, "Protocol error - ~p", [?RC_TOPIC_ALIAS_INVALID], PState),
+            {error, ?RC_TOPIC_ALIAS_INVALID, PState};
         {error, ReasonCode} ->
             ?LOG(warning, "Cannot publish qos0 message to ~s for ~s", [Topic, ReasonCode], PState),
-            {ok, PState}
+            {error, ReasonCode, PState}
     end;
 
 process_packet(Packet = ?PUBLISH_PACKET(?QOS_1, PacketId), PState) ->
@@ -644,9 +647,11 @@ check_publish(Packet, PState) ->
     run_check_steps([fun check_pub_caps/2,
                      fun check_pub_acl/2], Packet, PState).
 
-check_pub_caps(#mqtt_packet{header = #mqtt_packet_header{qos = QoS, retain = R}},
+check_pub_caps(#mqtt_packet{header = #mqtt_packet_header{qos = QoS, retain = Retain},
+                            variable = #mqtt_packet_publish{ properties = Properties}},
                #pstate{zone = Zone}) ->
-    emqx_mqtt_caps:check_pub(Zone, #{qos => QoS, retain => R}).
+    #{'Topic-Alias' := TopicAlias} = Properties,
+    emqx_mqtt_caps:check_pub(Zone, #{qos => QoS, retain => Retain, topic_alias => TopicAlias}).
 
 check_pub_acl(_Packet, #pstate{is_super = IsSuper, enable_acl = EnableAcl})
     when IsSuper orelse (not EnableAcl) ->
diff --git a/test/emqx_mqtt_caps_SUITE.erl b/test/emqx_mqtt_caps_SUITE.erl
index 85f6fae1d..d5751f9bb 100644
--- a/test/emqx_mqtt_caps_SUITE.erl
+++ b/test/emqx_mqtt_caps_SUITE.erl
@@ -38,7 +38,7 @@ t_get_set_caps(_) ->
         mqtt_wildcard_subscription => true
     },
     Caps2 = Caps#{max_packet_size => 1048576},
-    case emqx_mqtt_caps:get_caps(zone) of 
+    case emqx_mqtt_caps:get_caps(zone) of
         Caps -> ok;
         Caps2 -> ok
     end,
@@ -64,20 +64,28 @@ t_check_pub(_) ->
     {ok, _} = emqx_zone:start_link(),
     PubCaps = #{
         max_qos_allowed => ?QOS_1,
-        mqtt_retain_available => false
+        mqtt_retain_available => false,
+        max_topic_alias => 4
     },
     emqx_zone:set_env(zone, '$mqtt_pub_caps', PubCaps),
     timer:sleep(100),
+    ct:log("~p", [emqx_mqtt_caps:get_caps(zone, publish)]),
     BadPubProps1 = #{
         qos => ?QOS_2,
         retain => false
-    }, 
+    },
     {error, ?RC_QOS_NOT_SUPPORTED} = emqx_mqtt_caps:check_pub(zone, BadPubProps1),
     BadPubProps2 = #{
         qos => ?QOS_1,
         retain => true
-    }, 
+    },
     {error, ?RC_RETAIN_NOT_SUPPORTED} = emqx_mqtt_caps:check_pub(zone, BadPubProps2),
+    BadPubProps3 = #{
+        qos => ?QOS_1,
+        retain => false,
+        topic_alias => 5
+    },
+    {error, ?RC_TOPIC_ALIAS_INVALID} = emqx_mqtt_caps:check_pub(zone, BadPubProps3),
     PubProps = #{
         qos => ?QOS_1,
         retain => false
@@ -96,19 +104,19 @@ t_check_sub(_) ->
         mqtt_wildcard_subscription => true
     },
 
-    ok = do_check_sub([{<<"client/stat">>, Opts}], [{<<"client/stat">>, Opts}]), 
+    ok = do_check_sub([{<<"client/stat">>, Opts}], [{<<"client/stat">>, Opts}]),
     ok = do_check_sub(Caps#{max_qos_allowed => ?QOS_1}, [{<<"client/stat">>, Opts}], [{<<"client/stat">>, Opts#{qos => ?QOS_1}}]),
-    ok = do_check_sub(Caps#{max_topic_levels => 1}, 
-                        [{<<"client/stat">>, Opts}], 
+    ok = do_check_sub(Caps#{max_topic_levels => 1},
+                        [{<<"client/stat">>, Opts}],
                         [{<<"client/stat">>, Opts#{rc => ?RC_TOPIC_FILTER_INVALID}}]),
-    ok = do_check_sub(Caps#{mqtt_shared_subscription => false}, 
-                        [{<<"client/stat">>, Opts}], 
+    ok = do_check_sub(Caps#{mqtt_shared_subscription => false},
+                        [{<<"client/stat">>, Opts}],
                         [{<<"client/stat">>, Opts#{rc => ?RC_SHARED_SUBSCRIPTIONS_NOT_SUPPORTED}}]),
+
     ok = do_check_sub(Caps#{mqtt_wildcard_subscription => false}, 
                         [{<<"vlient/+/dsofi">>, Opts}], 
                         [{<<"vlient/+/dsofi">>, Opts#{rc => ?RC_WILDCARD_SUBSCRIPTIONS_NOT_SUPPORTED}}]),
     emqx_zone:stop().
-