The invention relates to the technical field of plastic packaging boxes, specifically a plastic packaging box, including a plastic box, a top cover, a collision mechanism, a first pull rod, a second pull rod, a stop rod, a rotating shaft, a telescopic spring, a slide rod, and a fixed shaft , card slot and adjustment mechanism. In the present invention, by pulling the two stop rods, the distance between the second pull rod and the second pull rod is stretched under the action of the slide rod and the telescopic spring, and when it is rotated to a certain position, the slots on one side of the two stop rods are aligned. The corners at both ends of the top of the push rod are removed, and the pulling force is removed, so that the first pull rod and the second pull rod shrink under the action of the telescopic spring, so that the inside of the card slot on one side of the two stop rods is in contact with the top corner of the top cover, so that Two blocking rods lock the top cover to prevent easy opening or falling off. Under the action of two sets of first and second rods, it is beneficial to close and support the plastic box, which plays the role of anti-drop and compression resistance. The function of the regulating mechanism is conducive to regulating the ventilation inside the plastic box.