In a production process of an aluminum alloy wheel, spraying is a very important procedure, and the procedure is carried out to achieve a better appearance effect for the wheel. However, the procedure contains numerous steps, after spraying bottom powder and colored paint on the wheel for the first time, and before carrying out the next step, bottom powder on a ring flange of the wheel and at a center hole must be removed; at this time, if the bottom powder is removed manually, the efficiency is absolutely very low, and the effect is not good; and therefore, an automatic device is needed to quickly remove the bottom powder online.