Abstract: A plug connector includes an insulating housing, a plurality of detecting terminals, a plurality of connection terminals, an outer shell and at least one ground piece. The insulating housing has a plurality of connection terminal grooves and a plurality of detecting terminal grooves. The plurality of the detecting terminals are assembled in the plurality of the detecting terminal grooves separately. The plurality of the connection terminals are assembled in the plurality of the connection terminal grooves separately. The outer shell surrounds the insulating housing. A top surface of the outer shell protrudes upward and then is bent frontward to form a locking portion. The at least one ground piece is mounted to at least one side of the insulating housing, and a portion of the at least one ground piece is exposed outside from the insulating housing and the outer shell.