diff --git a/TinySTL/Detail/TireTree.cpp b/TinySTL/Detail/TireTree.cpp
index de0c7f64cf0a34373db81f51d91e9947a9d7f6d1..177de7647a376019c4ce8fef9b0c841960dc7927 100644
--- a/TinySTL/Detail/TireTree.cpp
+++ b/TinySTL/Detail/TireTree.cpp
@@ -1,17 +1,19 @@
 #include "../TrieTree.h"
 
 namespace TinySTL{
-	trie_tree::trie_tree(){
-		data = new trie_node;
-		data->is_a_word = false;
-		data->map_childs.clear();
-	}
+	trie_tree::trie_tree():data(new trie_node), size_(0){}
 	trie_tree::~trie_tree(){
 		if (data){
 			data->map_childs.clear();
 			delete data;
 		}
 	}
+	bool trie_tree::empty()const{
+		return size() == 0;
+	}
+	trie_tree::size_type trie_tree::size()const{
+		return size_;
+	}
 	bool trie_tree::is_existed(const string& word)const{
 		if (word.empty())
 			return false;
@@ -41,8 +43,7 @@ namespace TinySTL{
 		auto root = get_root();
 		auto res = root->map_childs.find(ch);
 		if (res != root->map_childs.end()){
-			string tmp_word(word.substr(1));
-			return _insert(tmp_word, res->second);
+			return _insert(word.substr(1), res->second);
 		}else{
 			auto new_sp = std::make_shared<trie_node>();
 			new_sp->data = ch;
@@ -53,6 +54,7 @@ namespace TinySTL{
 	}
 	bool trie_tree::_insert(const string& word, std::shared_ptr<trie_node> sp){
 		if (word.empty()){
+			++size_;
 			sp->is_a_word = true;
 			return true;
 		}
@@ -97,6 +99,8 @@ namespace TinySTL{
 	void trie_tree::_get_word_by_prefix(const string& prefix, std::shared_ptr<trie_node> sp,
 		const string& real_prefix, vector<string>& words)const{
 		if (prefix.size() == 1){
+			if (sp->is_a_word)
+				words.push_back(real_prefix);
 			for (auto cit = sp->map_childs.cbegin(); cit != sp->map_childs.cend(); ++cit){
 				__get_word_by_prefix(cit->second, string(), real_prefix, words);
 			}
diff --git a/TinySTL/Test/TrieTreeTest.cpp b/TinySTL/Test/TrieTreeTest.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..2bffca88b11efc27b79eea24c5fcf9ba4a9e2bdc
--- /dev/null
+++ b/TinySTL/Test/TrieTreeTest.cpp
@@ -0,0 +1,44 @@
+#include "TrieTreeTest.h"
+
+namespace TinySTL{
+	namespace TrieTreeTest{
+		void testCase1(){
+			trie_tree t;
+			t.insert("abc");
+			t.insert("def");
+
+			assert(t.is_existed("abc"));
+			assert(!t.is_existed("a"));
+		}
+		void testCase2(){
+			trie_tree t;
+			string arr[] = { "ab", "abbreviation", "abide", "abolish", "abstract"};
+			for (const auto& str : arr){
+				t.insert(str);
+			}
+			t.insert("action");
+
+			auto v = t.get_word_by_prefix("ab");
+			assert(TinySTL::Test::container_equal(v, arr));
+		}
+		void testCase3(){
+			trie_tree t;
+			string arr[] = { "a", "ab", "abc", "d", "a", "abc" };
+
+			assert(t.empty());
+			assert(t.size() == 0);
+
+			for (const auto& str : arr){
+				t.insert(str);
+			}
+			assert(!t.empty());
+			assert(t.size() == 4);
+		}
+
+		void testAllCases(){
+			testCase1();
+			testCase2();
+			testCase3();
+		}
+	}
+}
\ No newline at end of file
diff --git a/TinySTL/Test/TrieTreeTest.h b/TinySTL/Test/TrieTreeTest.h
new file mode 100644
index 0000000000000000000000000000000000000000..5501371fe11d06f64d54525e4a82588245cd41cc
--- /dev/null
+++ b/TinySTL/Test/TrieTreeTest.h
@@ -0,0 +1,20 @@
+#ifndef _TRIE_TREE_TEST_H_
+#define _TRIE_TREE_TEST_H_
+
+#include "TestUtil.h"
+
+#include "../TrieTree.h"
+
+#include <cassert>
+
+namespace TinySTL{
+	namespace TrieTreeTest{
+		void testCase1();
+		void testCase2();
+		void testCase3();
+
+		void testAllCases();
+	}
+}
+
+#endif
\ No newline at end of file
diff --git a/TinySTL/TrieTree.h b/TinySTL/TrieTree.h
index b6afbb0432ae1329435f0f08b78b4b02216a3f88..2d163bd619229c421f5dddd09875dd4262576983 100644
--- a/TinySTL/TrieTree.h
+++ b/TinySTL/TrieTree.h
@@ -16,15 +16,23 @@ namespace TinySTL{
 			char data;
 			bool is_a_word;
 			std::map<char, std::shared_ptr<trie_node>> map_childs;
+			trie_node() :data('\0'), is_a_word(false){}
 		};
+	public:
+		typedef string value_type;
+		typedef size_t size_type;
 	private:
 		trie_node *data;
+		size_type size_;
 	public:
 		trie_tree();
 		~trie_tree();
 		trie_tree(const trie_tree&) = delete;
 		trie_tree& operator = (const trie_tree&) = delete;
 
+		bool empty()const;
+		size_type size()const;
+
 		vector<string> get_word_by_prefix(const string& prefix)const;
 		void print_tree(std::ostream& os = std::cout)const;
 		bool insert(const string& word);