A tool for manually disassembling motor vehicle tyres comprises a large gear, a rotating arm, a small gear and a separation plug, one end of the rotating arm is rotatably hinged to the center of the large gear through a hinge pin, the center of the small gear is fixedly connected to a driving shaft, and the driving shaft is rotatably installed on the rotating arm and meanwhile enables the small gear and the large gear to form a mutually engaged relationship; and the separation plug is arranged on the other end of the rotating arm, the position of the separation plug on the rotating arm can be adjusted and fixed through a screw, and a plurality of long-strip-shaped holes which are evenly distributed circumferentially are formed in the radial direction of the large gear. The tool for manually disassembling the motor vehicle tyres has the advantages of being convenient to use and good in using effect in the process of separating the tyres and wheel hubs.