The invention discloses a coating preparation device added with high-purity nanometer aluminum oxide. The coating preparation device comprises a support frame, a spraying hole and a stirring shaft, wherein a raw material inlet is formed above the support frame; a grinding device is connected under the raw material inlet; a vibration screening device is connected under the right side of the grinding device; a spiral shaft is arranged in a mixing drum; a stirring tank is connected under a mixture outlet; a driving device is connected with one side of the stirring shaft; and a liquid filling port is formed in a joint of the stirring shaft and the support frame. The coating preparation device added with high-purity nanometer aluminum oxide is creatively designed on the basis of the coating preparation device generally used at present; the grinding device and the vibration screening device are arranged in the device, so that the caked raw material is prevented from entering the stirring device; and meanwhile, a stepped processing method is adopted by the device, so that the device can extremely reduce the time of halting caused by raw material addition, the quality of end products is increased, and the processing time is reduced.