Anodic alumina in aluminum and aluminum alloy surface coated with a layer of dense alumina in order to prevent further oxidation, its chemistry the same as the alumina. But contrary to the oxide film, anodic aluminum oxide electrolytic coloring can be used to dye. Anodic oxidation can significantly improve the corrosion resistance of aluminum alloy, improve the surface hardness and wear resistance of aluminum alloy, after dealing with the appropriate color has a good decorative performance.