The invention discloses an automatic magnet washing method. The automatic magnet washing method adopts an automatic magnetic washing device, and the automatic washing device comprises a turntable withthe attraction to a magnet, a cleaning mechanism and a washing structure; and the cleaning mechanism comprises a guide rod, two sliding columns, two mounting discs with respect to the center of the turntable, two distance sensors mounted on the side faces of the two sliding columns respectively, a plurality of brushes, two threaded rods parallel to the guide rod and with the thread rotation direction opposite to that of the guide rod, and the washing structure comprises a nozzle. The automatic washing method include the steps of 1, the magnet is absorbed on the turntable, the threaded rods are rotated, when the distance from the sliding columns to the turntable by the distance sensors reaches the first preset distance, the turntable and the mounting discs are rotated, and the brushes rotates along with the mounting discs so as to clean the magnet adsorbed on the turntable; and 2, after the turntable and the mounting discs are rotated to the first preset time, and the nozzle is opened.The automatic magnetic washing device facilitates the washing of the operators, avoids the damage that may be caused by manual washing, and improves the washing efficiency.