Magnesium alloys were treated by micro-arc oxidation at a constant applied current density. The friction and wear properties were investigated by optical microscope and universal friction and wear tester in 3.5%NaCl solution. The result reveals that the film formed by micro-arc oxidation enhances the corrosion resistance of the magnesium alloys. The Ecorr of micro-arc oxidation film improved 94mV than the Ecorr of magnesium alloys matrix. Wear resistance of the film was weakened in 3.5%NaCl solution. The wear mechanism of film depends on the load. Abrasive wear was predominant at low load. Peeling wear was predominant at high load, which result from damage of the film adhesion.