If I understand you correctly ...you only want to allow specific people and groups to start a process?
If so they must be given the right to Invoke the process from teh SEcurity tab in the adminui for that specific process. This will allow the category that the process is in to appear in the Start Processes panel when they log into workbench.
Hi Paul , thank you very much ! I've got it .
we did a lot of test on user management a long time ago , and I found that most of the users had the right "ContentSpace User " , that is the cause which make me puzzled . Now , I remove the right for some users , and it can work correctly now .
Thank you !