A collapsible cat litter box includes a top cover and a bottom basin. The bottom basin is fixable to the top cover by screws and nuts. The bottom basin and the top cover are provided with holes cooperating with the screws and nuts. Two screw-holes are provided at each of two ends of the bottom basin and two screw-holes are provided at each of two ends of the top cover. The top cover is provided with an opening for a cat to enter and exit. A body of the top cover is collapsible. The top cover is made of a blow-molded material.
