diff --git a/src/KeyWordExt.cpp b/src/KeyWordExt.cpp
index f3f92b5..55c7beb 100644
--- a/src/KeyWordExt.cpp
+++ b/src/KeyWordExt.cpp
@@ -21,17 +21,17 @@ namespace CppJieba
 		return _segment.init();
 	}
 
-	bool KeyWordExt::loadSegDict(const string& filePath)
+	bool KeyWordExt::loadSegDict(const char * const filePath)
 	{
 		return _segment.loadSegDict(filePath);
 	}
 
-	bool KeyWordExt::loadPriorSubWords(const string& filePath)
+	bool KeyWordExt::loadPriorSubWords(const char * const filePath)
 	{
-		LogInfo(string_format("loadPriorSubWords(%s) start", filePath.c_str()));
-		if(!checkFileExist(filePath.c_str()))
+		LogInfo(string_format("loadPriorSubWords(%s) start", filePath));
+		if(!checkFileExist(filePath))
 		{
-			LogError(string_format("cann't find file[%s].",filePath.c_str()));
+			LogError(string_format("cann't find file[%s].",filePath));
 			return false;
 		}
 		if(!_priorSubWords.empty())
@@ -39,33 +39,33 @@ namespace CppJieba
 			LogError("_priorSubWords has been initted before");
 			return false;
 		}
-		ifstream infile(filePath.c_str());
+		ifstream infile(filePath);
 		string subword;
 		while(getline(infile, subword))
 		{
 			_priorSubWords.push_back(subword);
 		}
-		LogInfo(string_format("loadPriorSubWords(%s) end", filePath.c_str()));
+		LogInfo(string_format("loadPriorSubWords(%s) end", filePath));
 		infile.close();
 		return true;
 	}
 
-	bool KeyWordExt::loadStopWords(const string& filePath)
+	bool KeyWordExt::loadStopWords(const char * const filePath)
 	{
 
-		LogInfo(string_format("loadStopWords(%s) start", filePath.c_str()));
+		LogInfo(string_format("loadStopWords(%s) start", filePath));
 		if(!_stopWords.empty())
 		{
 			LogError("_stopWords has been loaded before! ");
 			return false;
 		}
-		if(!checkFileExist(filePath.c_str()))
+		if(!checkFileExist(filePath))
 		{
-			LogError(string_format("cann't find file[%s].",filePath.c_str()));
+			LogError(string_format("cann't find file[%s].",filePath));
 			return false;
 		}
 
-		ifstream ifile(filePath.c_str());
+		ifstream ifile(filePath);
 		string line;
 		while(getline(ifile, line))
 		{
diff --git a/src/KeyWordExt.h b/src/KeyWordExt.h
index 2049f8b..f204211 100644
--- a/src/KeyWordExt.h
+++ b/src/KeyWordExt.h
@@ -50,13 +50,13 @@ namespace CppJieba
 			~KeyWordExt();
 			bool init();
 
-			bool loadSegDict(const string& filePath);
+			bool loadSegDict(const char * const filePath);
 
 			//load stopwords
-			bool loadStopWords(const string& filePath);
+			bool loadStopWords(const char * const filePath);
 
 			//load prior words' prefix
-			bool loadPriorSubWords(const string& filePath);
+			bool loadPriorSubWords(const char * const filePath);
 
 			bool dispose();
 
diff --git a/src/Segment.cpp b/src/Segment.cpp
index edbdfb2..8254b39 100644
--- a/src/Segment.cpp
+++ b/src/Segment.cpp
@@ -25,9 +25,9 @@ namespace CppJieba
 		return true;
 	}
 	
-	bool Segment::loadSegDict(const string& filePath)
+	bool Segment::loadSegDict(const char * const filePath)
 	{
-		LogInfo(string_format("_trie.loadDict(%s) start...", filePath.c_str()));
+		LogInfo(string_format("_trie.loadDict(%s) start...", filePath));
 		bool retFlag = _trie.loadDict(filePath);
 		LogInfo("_trie.loadDict end.");
 		return retFlag;
diff --git a/src/Segment.h b/src/Segment.h
index a5374a2..1526411 100644
--- a/src/Segment.h
+++ b/src/Segment.h
@@ -21,7 +21,7 @@ namespace CppJieba
 			~Segment();
 		public:
 			bool init();
-			bool loadSegDict(const string& filePath);
+			bool loadSegDict(const char * const filePath);
 			bool dispose();
 			double getWordWeight(const string& str);
 		public:
diff --git a/src/Trie.cpp b/src/Trie.cpp
index 6880ea0..71251e5 100644
--- a/src/Trie.cpp
+++ b/src/Trie.cpp
@@ -63,7 +63,7 @@ namespace CppJieba
 		return true;
 	}
 
-	bool Trie::loadDict(const string& filePath)
+	bool Trie::loadDict(const char * const filePath)
 	{
 		if(!_getInitFlag())
 		{
@@ -71,9 +71,9 @@ namespace CppJieba
 			return false;
 		}
 
-		if(!checkFileExist(filePath.c_str()))
+		if(!checkFileExist(filePath))
 		{
-			LogError(string_format("cann't find fiel[%s].",filePath.c_str()));
+			LogError(string_format("cann't find fiel[%s].",filePath));
 			return false;
 		}
 		bool res = false;
@@ -92,10 +92,10 @@ namespace CppJieba
 		return true;
 	}
 
-    bool Trie::_buildTree(const string& filePath)
+    bool Trie::_buildTree(const char * const filePath)
     {
 		
-        ifstream ifile(filePath.c_str());
+        ifstream ifile(filePath);
         string line;
         vector<string> vecBuf;
         while(getline(ifile, line))
diff --git a/src/Trie.h b/src/Trie.h
index 39c5a40..39e3a91 100644
--- a/src/Trie.h
+++ b/src/Trie.h
@@ -77,7 +77,7 @@ namespace CppJieba
             Trie();
             ~Trie();
             bool init();
-			bool loadDict(const string& filePath);
+			bool loadDict(const char * const filePath);
             bool dispose();
 
 		private:
@@ -101,7 +101,7 @@ namespace CppJieba
 			bool insert(const TrieNodeInfo& nodeInfo);
 
         private:
-			bool _buildTree(const string& filePath);
+			bool _buildTree(const char * const filePath);
 			bool _countWeight();
             bool _deleteNode(TrieNode* node);