diff --git a/TinySTL/Detail/COWPtr.impl.h b/TinySTL/Detail/COWPtr.impl.h
new file mode 100644
index 0000000000000000000000000000000000000000..69711f5a8599fd65b9f40e008b9b1747773dd313
--- /dev/null
+++ b/TinySTL/Detail/COWPtr.impl.h
@@ -0,0 +1,32 @@
+#ifndef _COWPTR_IMPL_H_
+#define _COWPTR_IMPL_H_
+
+namespace TinySTL{
+	template<class T>
+	cow_ptr<T>::cow_ptr(T *p = nullptr) :ptr_(p){}
+	template<class T>
+	template<class D>
+	cow_ptr<T>::cow_ptr(T *p, D d) : ptr_(p, d){}
+	template<class T>
+	cow_ptr<T>::cow_ptr(const cow_ptr& cp){
+		ptr_ = cp.ptr_;
+	}
+	template<class T>
+	cow_ptr<T>& cow_ptr<T>::operator = (const cow_ptr& cp){
+		if (this != &cp){
+			ptr_.decrease_ref();
+			ptr_ = cp.ptr_;
+		}
+		return *this;
+	}
+	template<class T>
+	typename cow_ptr<T>::element_type cow_ptr<T>::operator *()const{
+		return *ptr_;
+	}
+	template<class T>
+	typename cow_ptr<T>::element_type *cow_ptr<T>::operator ->()const{
+		return ptr_.operator->();
+	}
+}
+
+#endif
\ No newline at end of file
diff --git a/TinySTL/Test/COWPtrTest.cpp b/TinySTL/Test/COWPtrTest.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..f5cf34783eb1644606165940ed4aae137bcdec42
--- /dev/null
+++ b/TinySTL/Test/COWPtrTest.cpp
@@ -0,0 +1,24 @@
+#include "COWPtrTest.h"
+
+#include "../String.h"
+
+namespace TinySTL{
+	namespace COWPtrTest{
+		void testCase1(){
+			cow_ptr<string> cp1(new string("hello"));
+			assert(*cp1 == "hello");
+			
+			cp1->append(" world");
+			auto cp2 = cp1;
+			assert(*cp2 == "hello world");
+
+			cow_ptr<string> cp3;
+			cp3 = cp1;
+			assert(*cp3 == "hello world");
+		}
+
+		void testAllCases(){
+			testCase1();
+		}
+	}
+}
\ No newline at end of file
diff --git a/TinySTL/Test/COWPtrTest.h b/TinySTL/Test/COWPtrTest.h
new file mode 100644
index 0000000000000000000000000000000000000000..bb7499d9becb2cd93c536d2278dc2d61f21434be
--- /dev/null
+++ b/TinySTL/Test/COWPtrTest.h
@@ -0,0 +1,16 @@
+#ifndef _COWPTR_TEST_H_
+#define _COWPTR_TEST_H_
+
+#include "../COWPtr.h"
+
+#include <cassert>
+
+namespace TinySTL{
+	namespace COWPtrTest{
+		void testCase1();
+
+		void testAllCases();
+	}
+}
+
+#endif
\ No newline at end of file
diff --git a/TinySTL/TinySTL.vcxproj b/TinySTL/TinySTL.vcxproj
index 222161f3ff328d6a73bb70325ad5920b92e6cb93..89016799a8a1bde8f59e173b79352565d656e54e 100644
--- a/TinySTL/TinySTL.vcxproj
+++ b/TinySTL/TinySTL.vcxproj
@@ -82,7 +82,7 @@
   <ItemGroup>
     <ClCompile Include="Detail\Alloc.cpp" />
     <ClCompile Include="Detail\String.cpp" />
-    <ClCompile Include="Detail\TireTree.cpp" />
+    <ClCompile Include="Detail\TrieTree.cpp" />
     <ClCompile Include="main.cpp" />
     <ClCompile Include="Profiler\Profiler.cpp" />
     <ClCompile Include="Test\AlgorithmTest.cpp" />
@@ -90,6 +90,7 @@
     <ClCompile Include="Test\BinarySearchTreeTest.cpp" />
     <ClCompile Include="Test\BitmapTest.cpp" />
     <ClCompile Include="Test\CircularBufferTest.cpp" />
+    <ClCompile Include="Test\COWPtrTest.cpp" />
     <ClCompile Include="Test\DequeTest.cpp" />
     <ClCompile Include="Test\GraphTest.cpp" />
     <ClCompile Include="Test\ListTest.cpp" />
@@ -115,11 +116,13 @@
     <ClInclude Include="Bitmap.h" />
     <ClInclude Include="CircularBuffer.h" />
     <ClInclude Include="Construct.h" />
+    <ClInclude Include="COWPtr.h" />
     <ClInclude Include="Deque.h" />
     <ClInclude Include="Detail\AVLTree.impl.h" />
     <ClInclude Include="Detail\BinarySearchTree.impl.h" />
     <ClInclude Include="Detail\Bitmap.impl.h" />
     <ClInclude Include="Detail\CircularBuffer.impl.h" />
+    <ClInclude Include="Detail\COWPtr.impl.h" />
     <ClInclude Include="Detail\Deque.impl.h" />
     <ClInclude Include="Detail\Graph.impl.h" />
     <ClInclude Include="Detail\List.impl.h" />
@@ -142,6 +145,7 @@
     <ClInclude Include="Test\BinarySearchTreeTest.h" />
     <ClInclude Include="Test\BitmapTest.h" />
     <ClInclude Include="Test\CircularBufferTest.h" />
+    <ClInclude Include="Test\COWPtrTest.h" />
     <ClInclude Include="Test\DequeTest.h" />
     <ClInclude Include="Test\GraphTest.h" />
     <ClInclude Include="Test\ListTest.h" />
diff --git a/TinySTL/TinySTL.vcxproj.filters b/TinySTL/TinySTL.vcxproj.filters
index b8069281aaf2901fe091e549902a4f6f20ac2c6a..166fc9779f5f07a5580e64af142d2c63590fa4b5 100644
--- a/TinySTL/TinySTL.vcxproj.filters
+++ b/TinySTL/TinySTL.vcxproj.filters
@@ -90,9 +90,6 @@
     <ClCompile Include="Test\GraphTest.cpp">
       <Filter>Test</Filter>
     </ClCompile>
-    <ClCompile Include="Detail\TireTree.cpp">
-      <Filter>Detail</Filter>
-    </ClCompile>
     <ClCompile Include="Test\TrieTreeTest.cpp">
       <Filter>Test</Filter>
     </ClCompile>
@@ -105,6 +102,12 @@
     <ClCompile Include="Test\SharedPtrTest.cpp">
       <Filter>Test</Filter>
     </ClCompile>
+    <ClCompile Include="Detail\TrieTree.cpp">
+      <Filter>Detail</Filter>
+    </ClCompile>
+    <ClCompile Include="Test\COWPtrTest.cpp">
+      <Filter>Test</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="TypeTraits.h">
@@ -278,6 +281,15 @@
     <ClInclude Include="Test\SharedPtrTest.h">
       <Filter>Test</Filter>
     </ClInclude>
+    <ClInclude Include="COWPtr.h">
+      <Filter>头文件</Filter>
+    </ClInclude>
+    <ClInclude Include="Detail\COWPtr.impl.h">
+      <Filter>Detail</Filter>
+    </ClInclude>
+    <ClInclude Include="Test\COWPtrTest.h">
+      <Filter>Test</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <None Include="..\README.md" />
diff --git a/TinySTL/main.cpp b/TinySTL/main.cpp
index c6a1757a1963a20cf3992a69bbbd718020bb9fb5..4c8bd6045237ef05c2b9ea16f33388ee273b8868 100644
--- a/TinySTL/main.cpp
+++ b/TinySTL/main.cpp
@@ -8,6 +8,7 @@
 #include "Test\BitmapTest.h"
 #include "Test\BinarySearchTreeTest.h"
 #include "Test\CircularBufferTest.h"
+#include "Test\COWPtrTest.h"
 #include "Test\DequeTest.h"
 #include "Test\GraphTest.h"
 #include "Test\ListTest.h"
@@ -32,6 +33,7 @@ int main(){
 	TinySTL::BitmapTest::testAllCases();
 	TinySTL::BinarySearchTreeTest::testAllCases();
 	TinySTL::CircularBufferTest::testAllCases();
+	TinySTL::COWPtrTest::testAllCases();
 	TinySTL::DequeTest::testAllCases();
 	TinySTL::ListTest::testAllCases();
 	TinySTL::GraphTest::testAllCases();