diff --git a/ChangeLog.md b/ChangeLog.md
index 094f747..a55ff04 100644
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -4,6 +4,7 @@
 
 + 在 Trie 中去除之前糟糕的针对 uint16 优化的用数组代替 map 的设计，
 该设计的主要问题是前提 unicode 每个字符必须是 uint16 ，则无法更全面得支持 unicode 多国字符。 
++ Rune 类型从 16bit 更改为 32bit ，支持更多 Unicode 字符，包括一些罕见汉字。
 
 ## v4.4.1
 
diff --git a/include/cppjieba/HMMModel.hpp b/include/cppjieba/HMMModel.hpp
index 05f2b72..e14b956 100644
--- a/include/cppjieba/HMMModel.hpp
+++ b/include/cppjieba/HMMModel.hpp
@@ -2,11 +2,12 @@
 #define CPPJIEBA_HMMMODEL_H
 
 #include "limonp/StringUtil.hpp"
+#include "Trie.hpp"
 
 namespace cppjieba {
 
 using namespace limonp;
-typedef unordered_map<uint16_t, double> EmitProbMap;
+typedef unordered_map<Rune, double> EmitProbMap;
 
 struct HMMModel {
   /*
@@ -70,7 +71,7 @@ struct HMMModel {
     CHECK(GetLine(ifile, line));
     CHECK(LoadEmitProb(line, emitProbS));
   }
-  double GetEmitProb(const EmitProbMap* ptMp, uint16_t key, 
+  double GetEmitProb(const EmitProbMap* ptMp, Rune key, 
         double defVal)const {
     EmitProbMap::const_iterator cit = ptMp->find(key);
     if (cit == ptMp->end()) {
diff --git a/include/cppjieba/TransCode.hpp b/include/cppjieba/TransCode.hpp
index 3e7690a..6320beb 100644
--- a/include/cppjieba/TransCode.hpp
+++ b/include/cppjieba/TransCode.hpp
@@ -13,7 +13,7 @@ namespace cppjieba {
 
 using namespace limonp;
 
-typedef uint16_t Rune;
+typedef uint32_t Rune;
 typedef limonp::LocalVector<Rune> Unicode;
 
 namespace TransCode {
@@ -21,7 +21,7 @@ inline bool Decode(const string& str, Unicode& res) {
 #ifdef CPPJIEBA_GBK
   return gbkTrans(str, res);
 #else
-  return Utf8ToUnicode(str, res);
+  return Utf8ToUnicode32(str, res);
 #endif
 }
 
@@ -29,7 +29,7 @@ inline void Encode(Unicode::const_iterator begin, Unicode::const_iterator end, s
 #ifdef CPPJIEBA_GBK
   gbkTrans(begin, end, res);
 #else
-  UnicodeToUtf8(begin, end, res);
+  Unicode32ToUtf8(begin, end, res);
 #endif
 }
 
diff --git a/include/cppjieba/Trie.hpp b/include/cppjieba/Trie.hpp
index fb5b9ff..6d1350a 100644
--- a/include/cppjieba/Trie.hpp
+++ b/include/cppjieba/Trie.hpp
@@ -4,6 +4,7 @@
 #include <vector>
 #include <queue>
 #include "limonp/StdExtension.hpp"
+#include "Trie.hpp"
 
 namespace cppjieba {
 
@@ -25,7 +26,7 @@ inline ostream & operator << (ostream& os, const DictUnit& unit) {
 }
 
 struct Dag {
-  uint16_t rune;
+  Rune rune;
   LocalVector<pair<size_t, const DictUnit*> > nexts;
   const DictUnit * pInfo;
   double weight;