diff --git a/apps/emqx_utils/src/emqx_placeholder.erl b/apps/emqx_utils/src/emqx_placeholder.erl
index edf4123e4..0f677236d 100644
--- a/apps/emqx_utils/src/emqx_placeholder.erl
+++ b/apps/emqx_utils/src/emqx_placeholder.erl
@@ -48,9 +48,13 @@
 
 -define(PH_VAR_THIS, '$this').
 
--define(EX_PLACE_HOLDER, "(\\$\\{[a-zA-Z0-9\\._]+\\})").
+%% To match any pattern starts with '$' and followed by '{', and closed by a '}' char:
+%% e.g. for string "a${abc}bb", "${abc}" will be matched.
+%% Note this is non-greedy matching
+%% e.g. if "${{abc}}" is given, the "${{abc}" should be matched, NOT "${{abc}}".
+-define(EX_PLACE_HOLDER, "(\\$\\{[^}]+\\})").
 
--define(EX_PLACE_HOLDER_DOUBLE_QUOTE, "(\\$\\{[a-zA-Z0-9\\._]+\\}|\"\\$\\{[a-zA-Z0-9\\._]+\\}\")").
+-define(EX_PLACE_HOLDER_DOUBLE_QUOTE, "(\\$\\{[^}]+\\}|\"\\$\\{[^}]+\\}\")").
 
 %% Space and CRLF
 -define(EX_WITHE_CHARS, "\\s").
diff --git a/apps/emqx_utils/src/emqx_utils.app.src b/apps/emqx_utils/src/emqx_utils.app.src
index 5900514dc..f8905b513 100644
--- a/apps/emqx_utils/src/emqx_utils.app.src
+++ b/apps/emqx_utils/src/emqx_utils.app.src
@@ -2,7 +2,7 @@
 {application, emqx_utils, [
     {description, "Miscellaneous utilities for EMQX apps"},
     % strict semver, bump manually!
-    {vsn, "5.0.5"},
+    {vsn, "5.0.6"},
     {modules, [
         emqx_utils,
         emqx_utils_api,
diff --git a/apps/emqx_utils/test/emqx_placeholder_SUITE.erl b/apps/emqx_utils/test/emqx_placeholder_SUITE.erl
index 81bf0853a..f813656f2 100644
--- a/apps/emqx_utils/test/emqx_placeholder_SUITE.erl
+++ b/apps/emqx_utils/test/emqx_placeholder_SUITE.erl
@@ -206,3 +206,53 @@ t_preproc_tmpl_deep(_) ->
         #{<<"${a}">> => [<<"1">>, "c", 2, 3.0, '${d}', {[<<"1.0">>], 0}]},
         emqx_placeholder:proc_tmpl_deep(Tmpl1, Selected)
     ).
+
+t_proc_tmpl_arbitrary_var_name(_) ->
+    Selected = #{
+        <<"中"/utf8>> => <<"1">>,
+        <<"中-1"/utf8>> => <<"1-1">>,
+        <<"-_+=<>,/?:;\"'\\[]|">> => 1,
+        <<"-_+=<>,">> => #{<<"/?:;\"'\\[]|">> => 2},
+        <<"!@#$%^&*()">> => 1.0,
+        <<"d">> => #{
+            <<"$ff">> => <<"oo">>,
+            <<"${f">> => <<"hi">>,
+            <<"${f}">> => <<"qq">>
+        }
+    },
+    Tks = emqx_placeholder:preproc_tmpl(
+        <<
+            "a:${中},a:${中-1},b:${-_+=<>,/?:;\"'\\[]|},"
+            "b:${-_+=<>,./?:;\"'\\[]|},c:${!@#$%^&*()},d:${d.$ff},d1:${d.${f}}"/utf8
+        >>
+    ),
+    ?assertEqual(
+        <<"a:1,a:1-1,b:1,b:2,c:1.0,d:oo,d1:hi}">>,
+        emqx_placeholder:proc_tmpl(Tks, Selected)
+    ).
+
+t_proc_tmpl_arbitrary_var_name_double_quote(_) ->
+    Selected = #{
+        <<"中"/utf8>> => <<"1">>,
+        <<"中-1"/utf8>> => <<"1-1">>,
+        <<"-_+=<>,/?:;\"'\\[]|">> => 1,
+        <<"-_+=<>,">> => #{<<"/?:;\"'\\[]|">> => 2},
+        <<"!@#$%^&*()">> => 1.0,
+        <<"d">> => #{
+            <<"$ff">> => <<"oo">>,
+            <<"${f">> => <<"hi">>,
+            <<"${f}">> => <<"qq">>
+        }
+    },
+    Tks = emqx_placeholder:preproc_tmpl(
+        <<
+            "a:\"${中}\",a:\"${中-1}\",b:\"${-_+=<>,/?:;\"'\\[]|}\","
+            "b:\"${-_+=<>,./?:;\"'\\[]|}\",c:\"${!@#$%^&*()}\",d:\"${d.$ff}\",d1:\"${d.${f}\"}"/utf8
+        >>,
+        #{strip_double_quote => true}
+    ),
+    ct:print("TKs:~p~n", [Tks]),
+    ?assertEqual(
+        <<"a:1,a:1-1,b:1,b:2,c:1.0,d:oo,d1:hi}">>,
+        emqx_placeholder:proc_tmpl(Tks, Selected)
+    ).
diff --git a/changes/ce/perf-11399.en.md b/changes/ce/perf-11399.en.md
new file mode 100644
index 000000000..42dac80bc
--- /dev/null
+++ b/changes/ce/perf-11399.en.md
@@ -0,0 +1,8 @@
+Improved the placeholder syntax of rule engine.
+
+The parameters of actions support using placeholder syntax to
+dynamically fill in the content of strings. The format of the
+placeholder syntax is `${key}`.
+Before this improvement, the `key` in `${key}` could only contain
+letters, numbers, and underscores. Now the `key` supports any UTF8
+characters.