In order to enhance the corrosion resistance of magnesium alloys， a micro arc oxidation coating was prepared on the surface of MB8 magnesium alloy using micro arc oxidation technology. The performance of the micro arc oxidation coating was characterized using X-ray diffraction （XRD）， scanning electron microscopy （SEM）， electrochemical workstation， and coating thickness measurement. Based on an orthogonal experimental method， the influences of duty cycle， frequency， and oxidation time on the thickness， surface porosity， and corrosion current density of the micro arc oxidation coating were investigated. The results reveal that， compared to MB8 magnesium alloy， the corrosion current density of the micro arc oxidation coating decreased by two orders of magnitude， indicating a significant improvement in corrosion resistance. The order of importance on the thickness， porosity， and corrosion resistance of the coating was found to be duty cycle， frequency， and oxidation time， respectively. At a fixed frequency， the surface porosity of the coating initially increases and then decreases as the duty cycle increases. The optimal performance of the membrane is achieved under conditions of a 50 % duty cycle， a frequency of 1.8 kHz， and an oxidation time of 15 minutes， resulting in a coating thickness of 18.6 μm， a porosity of 6.21%， and a corrosion current density of 2.56×10^-6 A/cm².