Mocking is not working

Are you using an Enterprise Edition (see this topic)?

Please tell me what results you are getting.

I am using community edition.

When i run test(Mocked and Unmocked) then Mocking on Mock test not working.
Example:
function()
{
try
{
MyClass.function2();
}
catch(Exception ex)
{
throw ex;
}
}

I want to cover my exception block(Catch)
for that i have written a mock test.
[Test]
public void FucntionTest()
{
MockManager.Init();
Mock MyClassMock = mockManager.Mock(typeof(MyClass));
MyClassMock.ExpectAndThrow("function2", new Exception);
function();
MyClassMock.Clear();
MyClassMock.Verify();
MockManager.Verify()
}

It is very hard to understand what is happening as your code doesn't compile and you are not sending what you expect to happen and what is actually happening.

If I understand your test, your function() shoudl throw the error so your test will never pass the function() call.
To check use the [ExpectedException(typeof(Exception))] attribute
or use the following pattern:

[Test] 
{ 
    <setuptest here>
    try {
      function();
      Asset.Fail("Should throw Exception");
    } catch (Exception ex) {
      <validate ex here>
    }
}