I want to validate my response ok or bad using Response Assertion.
I have set the Response Field to Test as Response Message.I have set Patterns to test as “ok”.
Bue the problem is,it shows green signal in result tree Listener even if i receive bad response. I have attached the screen shot.How to solve this?

This means that your response contains OK somewhere.
If you want to validate it returns a 200 code, check :
But also add a reponse assertion that check a text in you page, in this case replace OK by the text and check Text response / And substring.