Abstract: The overall process of micro-arc oxidation was described, and the principle of micro-arc oxidation film formation was systematically described. Then, based on the theoretical analysis obtained in the research process of micro-arc oxidation, the effect of breakdown discharge method on the micro-structure of the film layer in the process of micro-arc oxidation was discussed in detail. Finally, the influence mechanism of electrical parameters and electrolyte on the characteristics of the micro-arc oxidation film was expounded.