The process of forming micro arc oxide ceramic layer on the surface of magnesium alloy in high efficiency, low power consumption and high coating performance includes the first connecting the pre-treated magnesium alloy workpiece with the positive pole of great power pulse power source and setting in alkaline electrolyte solution compounded with deionized water and sodium silicate as main material inside an electrolytic bath with cathode of stainless steel, and micro arc oxidizing the surface of the magnesium alloy workpiece with asymmetrical AC pulse voltage in sectional applying mode. The sodium silicate electrolyte system is compounded with Na2SiO3.9H2O 30 g/L, NaOH or KOH 1-20 g/L, KF.2H2O 10-40 g/L, C3H5(OH)3 5-25 g/L, and NaAlO2.H2O or Na3C6H5O7.2H2O 5-50 g/L, and has pH value of 10-13. |