diff --git a/apps/emqx_rule_engine/src/emqx_rule_actions.erl b/apps/emqx_rule_engine/src/emqx_rule_actions.erl
index 83c13a3af..ae82d56c9 100644
--- a/apps/emqx_rule_engine/src/emqx_rule_actions.erl
+++ b/apps/emqx_rule_engine/src/emqx_rule_actions.erl
@@ -261,7 +261,7 @@ to_qos(TargetQoS) ->
 
 get_qos(-1, _Data, Default) -> Default;
 get_qos(TargetQoS, Data, _Default) ->
-    qos(emqx_rule_utils:replace_simple_var(TargetQoS, Data)).
+    qos(emqx_rule_utils:replace_var(TargetQoS, Data)).
 
 qos(<<"0">>) ->  0;
 qos(<<"1">>) ->  1;
@@ -285,7 +285,7 @@ to_retain(TargetRetain) ->
     end.
 
 get_retain(TargetRetain, Data) ->
-    retain(emqx_rule_utils:replace_simple_var(TargetRetain, Data)).
+    retain(emqx_rule_utils:replace_var(TargetRetain, Data)).
 
 retain(true) ->        true;
 retain(false) ->       false;
diff --git a/apps/emqx_rule_engine/src/emqx_rule_utils.erl b/apps/emqx_rule_engine/src/emqx_rule_utils.erl
index 047b9d1af..137e22128 100644
--- a/apps/emqx_rule_engine/src/emqx_rule_utils.erl
+++ b/apps/emqx_rule_engine/src/emqx_rule_utils.erl
@@ -16,8 +16,7 @@
 
 -module(emqx_rule_utils).
 
--export([ replace_vars_in_str/2
-        , replace_simple_var/2
+-export([ replace_var/2
         ]).
 
 %% preprocess and process tempalte string with place holders
@@ -91,20 +90,12 @@ preproc_tmpl([[Str, Phld]| Tokens], Acc) ->
 preproc_tmpl([[Str]| Tokens], Acc) ->
     preproc_tmpl(Tokens, put_head(str, Str, Acc)).
 
-%% Replace a string contains vars to another string in which the placeholders are replace by the
-%% corresponding values. For example, given "a: ${var}", if the var=1, the result string will be:
-%% "a: 1".
-replace_vars_in_str(Tokens, Data) when is_list(Tokens) ->
-    proc_tmpl(Tokens, Data, #{return => full_binary});
-replace_vars_in_str(Val, _Data) ->
-    Val.
-
 %% Replace a simple var to its value. For example, given "${var}", if the var=1, then the result
 %% value will be an integer 1.
-replace_simple_var(Tokens, Data) when is_list(Tokens) ->
-    [Var] = proc_tmpl(Tokens, Data, #{return => rawlist}),
-    Var;
-replace_simple_var(Val, _Data) ->
+replace_var(Tokens, Data) when is_list(Tokens) ->
+    [Val] = proc_tmpl(Tokens, Data, #{return => rawlist}),
+    Val;
+replace_var(Val, _Data) ->
     Val.
 
 put_head(_Type, <<>>, List) -> List;