I have sharepoint group with custom permission. I want this group to all access on site like admin except for "site collection feature" & "manage site feature". Is this possible? Which access I have to uncheck from custom permission (initial admin access is granted)
What you're looking for is called Permission Levels.
Permission Levels allows you to specify on a granular level what a user can and cannot do.
You can read more about the subject here: http://office.microsoft.com/en-za/sharepoint-server-help/edit-create-and-delete-permission-levels-HA101805381.aspx