The invention discloses a grinding device for coating processing. The grinding device comprises a grinding barrel, a motor, a transmission shaft, a stirring rod, a filtering plate and grinding balls; the grinding device is characterized in that the grinding barrel is arranged on a support, a feeding bin, a discharging bin, a water inlet pipe and a water outlet pipe are arranged on the grinding barrel, the motor is arranged at the bottom of the grinding barrel, the transmission shaft is arranged in the grinding barrel, and one end of the transmission shaft is connected with the motor; and the stirring rod is arranged on a connecting block, the filtering plate is arranged in the grinding barrel, and the grinding balls are arranged at the bottom of the grinding barrel and the position, above the filtering plate, in the grinding barrel. According to grinding device, the filtering plate is arranged in the grinding barrel, the grinding balls are arranged at the bottom of the grinding barrel and the position, above the filtering plate, in the grinding barrel, and therefore a coating raw material can be repeatedly ground, and the coating grinding quality is improved; and an interlayer is arranged on the grinding barrel, cooling water is injected into the interlayer, coating in the grinding process can be cooled, and the coating quality is further improved.