The invention belongs to the technical field of rubber processing, and discloses a rubber crushing method. The rubber crushing method comprises the steps of cleaning, cutting, sieving and impurity removal, wherein a rubber crushing device is adopted for cutting rubber, and comprises a machine body, a crushing bucket and a receiving bucket are arranged in the machine body, a first rotary shaft anda second rotary shaft are rotationally connected to the upper part of the crushing bucket, and a crushing roll knife is arranged on each of the first rotary shaft and the second rotary shaft; the rubber crushing device comprises a transmission mechanism, the transmission mechanism comprises a motor, a third rotary shaft, a drive belt wheel and a driven belt wheel, the motor drives the third rotaryshaft to rotate, and the drive belt wheel is installed on the third rotary shaft; the driven belt wheel is connected to the second rotary shaft, a belt is arranged between the drive belt wheel and the driven belt wheel, and each of the drive belt wheel and the driven belt wheel is conical; and a material-stopping plate is arranged on the sidewall of the crushing bucket, and an elastic element isarranged between the material-stopping plate and the inner wall of the crushing bucket. The rubber crushing method disclosed by the invention solves the problem of large particle sizes of the crushedrubber particles due to the fluctuation and weakening of a current in the prior art.