Abstract: 0.1% (mass fraction) mixed rare earth (RE) was added into ZM5 magnesium alloy to improve its ignition-proof performance.TGA curve,DSC curve,oxidation kinetics curves at constant temperatures of the alloy and XRD spectrum of the surface film were analyzed in order to investigate the surface oxidation behavior.The results show that adding 0.1%RE to ZM5 alloy improved its anti-oxidation performance,the starting oxidation temperature obviously increased from 300 ℃ to 500 ℃.And the oxide increase occurred mostly between 500℃ and 700℃,that the formed oxidation film after three kinds of oxidation reactions mainly consisted of RE2O3,MgO,Al2O3 and Mg17Al12.The oxidation kinetics curve of the alloy followed the parabola rule at 700 ℃,which proved that the compact oxidation film could prevent the matrix from further oxidation effectively.