Abstract: A new plastic tandem extrusion sizer mold. The mold includes an inlet plate, middle plates and an outlet plate which are connected with each other in series by columniform pin, and then side baffles are added to mount on a base with the aid of bolts. A rectangular inlet plate, middle plates and outlet plate, which constitute a cavity of different shape, are placed upright and connected together in sequence and in series. Compared with the conventional sizer mold, the present sizer mold gets over the limitations of cavity parting, machining deep holes, cutting gas slots, trivial design and complex manufacture process, and has a shortened design period and simplified technological process, and can be manufactured rapidly.