User Reference For a Particular role I am using Drupal 7 . and in a content type i created a field with user_reference,  which is working fine. 

And while creating a content it shows all users. 

Now i want to show  only User with particular role..  

Does anybody tell me how to do this. Is there is any module avialable for this
I would use the Entity Reference module (rather than user reference). I would then create a view (display: entity reference) filtering only Users with that desired role. 

In the field settings you can choose the designated View under "Entity Selection" - "Mode": "Views: Filter by an entity reference".

This is at least how I solved this problem in the past. I hope this helps.