The invention discloses a vibrating screen discharging outlet metal plate tool. One ends of the two sides of the bottom edge are fixed to a workbench through bolts. The middles of the two sides of a base plate are provided with T-shaped grooves. A pressing block is arranged on the base plate. Open slots are formed in the positions, opposite to the T-shaped grooves in the base plate, of the two sides of the pressing block. The pressing block is fixed to the base plate through lock bolts and lock nuts matched with the open slots and the T-shaped grooves. Hinge bases are arranged at the other ends of the two sides of the base plate respectively. Side plates are hinged to the hinge bases through rotating shafts. The tail ends of the side plates are connected through a handle. Bent plates which are in horizontal butt joint with the pressing block are arranged at the position, adjacent to the pressing block, between the side plates. The vibrating screen discharging outlet metal plate tool is simple in structure, convenient to use and suitable for metal plate machining of a vibrating screen discharging outlet with the polygonal special-shaped section.