diff --git a/demos/TTSCppFrontend/front_demo/front_demo.cpp b/demos/TTSCppFrontend/front_demo/front_demo.cpp
index 62b1945f7..0ac414a02 100644
--- a/demos/TTSCppFrontend/front_demo/front_demo.cpp
+++ b/demos/TTSCppFrontend/front_demo/front_demo.cpp
@@ -41,7 +41,7 @@ int main(int argc, char** argv) {
 
     // 繁体转简体
     std::wstring sentence_simp;
-    front_inst->Trand2Simp(ws_sentence, sentence_simp);
+    front_inst->Trand2Simp(ws_sentence, &sentence_simp);
     ws_sentence = sentence_simp;
 
     std::string s_sentence;
diff --git a/demos/TTSCppFrontend/src/front/front_interface.cpp b/demos/TTSCppFrontend/src/front/front_interface.cpp
index 4c21851f6..4f05f4b05 100644
--- a/demos/TTSCppFrontend/src/front/front_interface.cpp
+++ b/demos/TTSCppFrontend/src/front/front_interface.cpp
@@ -178,17 +178,17 @@ int FrontEngineInterface::ReadConfFile() {
 }
 
 int FrontEngineInterface::Trand2Simp(const std::wstring &sentence,
-                                     std::wstring &sentence_simp) {
+                                     std::wstring *sentence_simp) {
     // sentence_simp = sentence;
     for (int i = 0; i < sentence.length(); i++) {
         std::wstring temp(1, sentence[i]);
         std::string sigle_word = ppspeech::wstring2utf8string(temp);
         // 单个字是否在繁转简的字典里
         if (trand_simp_map.find(sigle_word) == trand_simp_map.end()) {
-            sentence_simp += temp;
+            sentence_simp->append(temp);
         } else {
-            sentence_simp +=
-                (ppspeech::utf8string2wstring(trand_simp_map[sigle_word]));
+            sentence_simp->append(
+                (ppspeech::utf8string2wstring(trand_simp_map[sigle_word])));
         }
     }
 
diff --git a/demos/TTSCppFrontend/src/front/front_interface.h b/demos/TTSCppFrontend/src/front/front_interface.h
index f766ac0eb..3628debaa 100644
--- a/demos/TTSCppFrontend/src/front/front_interface.h
+++ b/demos/TTSCppFrontend/src/front/front_interface.h
@@ -43,7 +43,7 @@ class FrontEngineInterface : public TextNormalizer {
     int ReadConfFile();
 
     // 简体转繁体
-    int Trand2Simp(const std::wstring &sentence, std::wstring &sentence_simp);
+    int Trand2Simp(const std::wstring &sentence, std::wstring *sentence_simp);
 
     // 生成字典
     int GenDict(const std::string &file,