The invention relates to a plastic compression molding machine, and belongs to the technical field of plastic molding equipment. The plastic compression molding machine comprises a base, wherein a workbench and mounting columns which are correspondingly matched with the workbench are arranged on the base respectively; an upper surface of the workbench is provided with an accommodating groove; a mounting seat is fixedly arranged at upper ends of the mounting columns; an oil cylinder is vertically arranged on the mounting seat; a piston rod of the oil cylinder faces vertically downwards and is connected with a lifting seat; an upper module which is correspondingly matched with the accommodating groove is fixedly arranged on a lower surface of the lifting seat. According to the plastic compression molding machine disclosed by the invention, a vertical structural design is adopted, so that the mounting space is saved, feeding is facilitated, and deviation of materials is prevented; the oilcylinder is taken as a power source, so that power output is stable, and the processing quality of products is enhanced.