i want to know Can i override the userlist menu item by create path of component in Html directory in template? such as other normal component?
No, CB views do not support template overrides. At this time only our modules do. Once we rewrite our template usage we'll be able to support Joomla layout overrides, but that probably won't be until CB 3.0.
in fact i want remove the first statement in top of the user list menu item that said: " sitename has 2 registered members"
That you can do by overriding its language string or hiding it with CSS. See the below for example.
www.joomlapolis.com/forum/153-professional-member-support/233886-solved-list-header-member-count?start=6#283069