diff --git a/apps/emqx_authz/src/emqx_authz_api_schema.erl b/apps/emqx_authz/src/emqx_authz_api_schema.erl
index 09f145075..27de5f693 100644
--- a/apps/emqx_authz/src/emqx_authz_api_schema.erl
+++ b/apps/emqx_authz/src/emqx_authz_api_schema.erl
@@ -484,7 +484,7 @@ definitions() ->
                 type => array,
                 items => #{
                   type => string,
-                  example => <<"{allow,{username,\"^dashboard?\"},subscribe,[\"$SYS/#\"]}.">>
+                  example => <<"{allow,{username,\"^dashboard?\"},subscribe,[\"$SYS/#\"]}.\n{allow,{ipaddr,\"127.0.0.1\"},all,[\"$SYS/#\",\"#\"]}.">>
                 }
             },
             path => #{
diff --git a/apps/emqx_authz/src/emqx_authz_api_sources.erl b/apps/emqx_authz/src/emqx_authz_api_sources.erl
index 209bbc01f..06b421e41 100644
--- a/apps/emqx_authz/src/emqx_authz_api_sources.erl
+++ b/apps/emqx_authz/src/emqx_authz_api_sources.erl
@@ -32,9 +32,8 @@
 -define(EXAMPLE_FILE,
         #{type=> file,
           enable => true,
-          rules => [<<"{allow,{username,\"^dashboard?\"},subscribe,[\"$SYS/#\"]}.">>,
-                    <<"{allow,{ipaddr,\"127.0.0.1\"},all,[\"$SYS/#\",\"#\"]}.">>
-                   ]}).
+          rules => <<"{allow,{username,\"^dashboard?\"},subscribe,[\"$SYS/#\"]}.\n{allow,{ipaddr,\"127.0.0.1\"},all,[\"$SYS/#\",\"#\"]}.">>
+                   }).
 
 -define(EXAMPLE_RETURNED_REDIS,
         maps:put(annotations, #{status => healthy}, ?EXAMPLE_REDIS)
@@ -350,9 +349,7 @@ sources(put, #{body := Body}) when is_list(Body) ->
     NBody = [ begin
                 case Source of
                     #{<<"type">> := <<"file">>, <<"rules">> := Rules, <<"enable">> := Enable} ->
-                        {ok, Filename} = write_file(filename:join([emqx:get_config([node, data_dir]), "acl.conf"]),
-                                                    erlang:list_to_bitstring([<<Rule/binary, "\n">> || Rule <- Rules])
-                                                   ),
+                        {ok, Filename} = write_file(filename:join([emqx:get_config([node, data_dir]), "acl.conf"]), Rules),
                         #{type => file, enable => Enable, path => Filename};
                     _ -> write_cert(Source)
                 end
@@ -396,9 +393,7 @@ source(get, #{bindings := #{type := Type}}) ->
             {200, read_cert(NSource2)}
     end;
 source(put, #{bindings := #{type := <<"file">>}, body := #{<<"type">> := <<"file">>, <<"rules">> := Rules, <<"enable">> := Enable}}) ->
-    {ok, Filename} = write_file(maps:get(path, emqx_authz:lookup(file), ""),
-                                erlang:list_to_bitstring([<<Rule/binary, "\n">> || Rule <- Rules])
-                               ),
+    {ok, Filename} = write_file(maps:get(path, emqx_authz:lookup(file), ""), Rules),
     case emqx_authz:update({replace_once, file}, #{type => file, enable => Enable, path => Filename}) of
         {ok, _} -> {204};
         {error, Reason} ->
diff --git a/apps/emqx_authz/test/emqx_authz_api_sources_SUITE.erl b/apps/emqx_authz/test/emqx_authz_api_sources_SUITE.erl
index 8c37189c9..104517b2a 100644
--- a/apps/emqx_authz/test/emqx_authz_api_sources_SUITE.erl
+++ b/apps/emqx_authz/test/emqx_authz_api_sources_SUITE.erl
@@ -92,10 +92,7 @@
                   }).
 -define(SOURCE6, #{<<"type">> => <<"file">>,
                    <<"enable">> => true,
-                   <<"rules">> =>
-                        [<<"{allow,{username,\"^dashboard?\"},subscribe,[\"$SYS/#\"]}.">>,
-                         <<"{allow,{ipaddr,\"127.0.0.1\"},all,[\"$SYS/#\",\"#\"]}.">>
-                        ]
+                   <<"rules">> => <<"{allow,{username,\"^dashboard?\"},subscribe,[\"$SYS/#\"]}.\n{allow,{ipaddr,\"127.0.0.1\"},all,[\"$SYS/#\",\"#\"]}.">>
                   }).
 
 all() ->