A method of anodic treatment for a metal workpiece combined with a non-metallic material includes steps as follows. A pretreatment process is applied to the metal workpiece. The metal workpiece is anodic oxidized, and washed with water. Then, the metal workpiece is put in a vacuum environment to evaporate a residual chemical agent between a metal part and a plastic part of the metal workpiece. The metal workpiece is washed with water. An activating treatment is applied to the metal workpiece. The metal workpiece is dyed, and is sealed.