The present invention provides a plug connector engaged with a socket. The plug connector includes an insulating body and a metal limiter. The insulating body has a mating port and a space for accommodating a circuit board, and the mating port is connected with the space. The metal limiter includes a metal bottom plate and a pair of metal side structures. The metal bottom plate is arranged under the opening of the mating port. The pair of metal side structures are respectively connected to the two sides of the metal bottom plate and arranged on the left and right sides of the opening to form a limiting space. When the plug connector is matched with the socket, the metal shell of the socket is sheathed with the front end of the insulating body, and the metal shell is located in the limiting space to restrict the plug connector from shaking.