The invention relates to a plastic packaging box. The plastic packaging box comprises a box body, a box cover, a connection bar and lugs, wherein the box body is connected with the box cover through the connection bar; grooves are formed in the lower end of the box body in the form of front-rear symmetry, the lugs are arranged at the upper end of the box cover in the form of front-rear symmetry, and the grooves form one-to-one correspondence with the lugs in position; and the box cover comprises a cover body, an auxiliary buckle, a clamping block, an elastic sheet and a press sheet. The invention further provides a production process for the plastic packaging box. The production process for the plastic packaging box comprises the steps of material mixing, injection die fixing, injection forming, die release, slitting, finish machining, and stacking and boxing, wherein a slitting device comprises a base plate, a workbench, a working cylinder, an installation frame, a location frame anda slitting tool. The plastic packaging box has the advantages of being firm in connection firmness for the box cover and the box body, high instability during stacking and transporting; and the slitting device has the advantages of being high in slitting accuracy, free from causing scratches to the plastic packaging box, capable of directly carrying out stacking, and the like.