The invention, which belongs to the electrical connector shielding technology, relates to a rectangular attachment capable of shielding a fixed wire, especially to a rectangular attachment capable ofshielding a fixed wire of an electric connector reliably. The rectangular attachment is characterized by comprising a shielding net and an attachment shell short-circuit mechanism; and a Ti-Ni ring (1), an adapter plate (4) and an adapter plate screw (9) are arranged. According to the rectangular attachment provided by the invention, conversion of a wire outlet of a rectangular product into a plurality of circular wire outlets is avoided and a requirement of usage in small and narrow space is met; a problem of difficult cooperation of a shielding net cover with four corners of the rectangularproduct is solved; the damage of the shielding net is avoided; and reliability of electrical continuity is ensured.