The characteristics of marine corrosion were analyzed, the morphology and corrosion resistance of micro-arc oxidation film and several common protective film were compared, the insulation property of micro-arc oxidation film and corrosion resistance after painting and electrophoresis were studied. The results show that: the oxide film with ceramic is formed on the surface of aluminum, magnesium and its alloys by micro-arc oxidation and then it is treated by spraying or electrophoresis process, which can effectively prevent pitting, crevice corrosion and galvanic corrosion occurs. It is a new way to prevent the corrosion of aluminum and magnesium alloy in the marine environment.