The anodized film of aluminum has high hardness, good corrosion resistance and abrasion resistance, and has good transparency so that the surface after the anodizing treatment maintains the original metal texture of the aluminum. However, Aluminum Alloy Die Cast Part participates in this very multi-metal material, which is prone to air defects, cold insulation, sand holes and other defects during the surface treatment of aluminum alloy die castings. Due to the second phase generated by the alloying elements and the electrode potential of the aluminum substrate Different, so the anodic oxidation behavior and mechanism of aluminum alloy is much more complicated than pure aluminum. At the same time, in addition to aluminum oxide and anions in solution, the composition of aluminum alloy anodic oxide film will inevitably have some alloying elements in aluminum alloy. A state, an oxide state, or an intermetallic compound state exists. Therefore, the appearance quality of the aluminum alloy die-casting oxidation treatment is poor, and the defect rate is high.