Using an alternative pulse current source and in silicate solution electrolyte，a uniform coating on the surface of AZ9lD alloy was fabricated by micro-arc oxidation(MAO) with current density of 40mA/cm2. Friction wear testing machine was used to study the wear behavior under corrosive environment of the film and scanning electron microscopy(SEM)were used to study microstructures of film and worn surface．The result shows that the corrosion resistance of micro-arc oxidation film is large better than that of magnesium alloy. The corrosive solution great weaken the abrasion resistance of the coating. As the influence of the corrosive solution, the wearing mechanism is varying with the loading. Abrasive wear is the main mechanism when the loading is small, if the loading is large enough, the binding force will be destroyed and the coating will peel off from magnesium alloy.