Abstract: The effect of alloying element Ce on oxidation behavior and surface tension of Mg-1.2Ca alloy was investigated in order to have a further develop for the ignition-proof magnesium alloys. As the content of Ce range from 0 to 1.5wt.%, the ignition point of Mg-1.2Ca increase rapidly while the surface tension decline. The ignition point of Mg-1.2Ca-1.2Ce alloy can reach to 780℃. And the Mg-1.2Ca-1.2Ce alloy can be melt at the atmosphere without any protection method. The oxidation film of Mg-1.2Ca melt has turned to fine and close structure from porous structure with Ce addition, which can prevent magnesium alloys from further oxidation and burning. According to the test and analysis, oxide film of Mg-1.2Ca-1.2Ce alloy consists of three layers which are loose MgO in the outer layer, MgO-CaO composite oxide film in the middle layer and MgO-Ce2O3 composite oxide film in the inner layer respectively.