diff --git a/common/include/input_hub.cpp b/common/include/input_hub.cpp
index afa54a5..1001041 100644
--- a/common/include/input_hub.cpp
+++ b/common/include/input_hub.cpp
@@ -424,7 +424,7 @@ void InputHub::ScanInputDevices(const std::string& dirName)
     DHLOGI("ScanInputDevices enter, dirName %s.", dirName.c_str());
     std::vector<std::string> vecInputDevPath;
     ScanInputDevicesPath(dirName, vecInputDevPath);
-    for (auto &tempPath: vecInputDevPath) {
+    for (const auto &tempPath: vecInputDevPath) {
         OpenInputDeviceLocked(tempPath);
     }
 }
diff --git a/utils/include/dinput_utils_tool.h b/utils/include/dinput_utils_tool.h
index 8092ce2..bb79969 100644
--- a/utils/include/dinput_utils_tool.h
+++ b/utils/include/dinput_utils_tool.h
@@ -53,9 +53,9 @@ std::string Sha256(const std::string& string);
 void CloseFd(int& fd);
 int BitIsSet(const unsigned long *array, int bit);
 void StringSplitToVector(const std::string& str, const char split, std::vector<std::string>& vecStr);
-int OpenInputDeviceFdByPath(std::string devicePath);
+int OpenInputDeviceFdByPath(const std::string &devicePath);
 std::string ConvertErrNo();
-void ScanInputDevicesPath(std::string dirName, std::vector<std::string>& vecInputDevPath);
+void ScanInputDevicesPath(const std::string &dirName, std::vector<std::string>& vecInputDevPath);
 } // namespace DistributedInput
 } // namespace DistributedHardware
 } // namespace OHOS
diff --git a/utils/src/dinput_utils_tool.cpp b/utils/src/dinput_utils_tool.cpp
index 659e93d..51a1b40 100644
--- a/utils/src/dinput_utils_tool.cpp
+++ b/utils/src/dinput_utils_tool.cpp
@@ -324,7 +324,7 @@ void StringSplitToVector(const std::string& str, const char split, std::vector<s
     }
 }
 
-int OpenInputDeviceFdByPath(std::string devicePath)
+int OpenInputDeviceFdByPath(const std::string &devicePath)
 {
     chmod(devicePath.c_str(), S_IWRITE | S_IREAD);
     char canonicalDevicePath[PATH_MAX] = {0x00};
@@ -362,7 +362,7 @@ std::string ConvertErrNo()
     return errNoMsg;
 }
 
-void ScanInputDevicesPath(std::string dirName, std::vector<std::string>& vecInputDevPath)
+void ScanInputDevicesPath(const std::string &dirName, std::vector<std::string>& vecInputDevPath)
 {
     DIR *dir;
     struct dirent *de;