The invention discloses a grain pulverizer. The grain pulverizer comprises a pulverizing chamber and a drive motor, wherein a pivot shaft is arranged in the pulverizing chamber; a pulverizing blade is arranged outside the pivot shaft; the pivot shaft is fixedly connected with the drive motor; a motor supporting part, a buffer spacer, a pivot shaft chuck and a motor fixing part are arranged between the pulverizing chamber and the drive motor. According to the grain pulverizer, the stability of the axis during rotation of the motor is greatly improved and the service life of the pulverizing blade is prolonged by using the motor supporting part and the motor fixing part which are arranged between the pulverizing chamber and the drive motor.