Strip casting process combines casting and hot rolling into a single step, with advantages of low equipment cost, low running cost, energy saving and space saving. Protective gases, such as SF₆ and Novec^TM612, should be used in order to prevent the ignition of magnesium alloys during strip casting. However, protective gases have disadvantages such as global warming, high production cost and corrosion of steel based equipments. According to the recent study, the addition of CaO is the effective way to improve the ignition and oxidation resistance of magnesium alloy. CaO added AZ31 magnesium alloy strip casting could be manufactured with reduced protective gas during melting and without protective gas during strip casting. The minimum SF₆ gas amount could be reduced under 50 ppm for 0.3 mass%CaO added AZ31 magnesium alloy both under sealed and unsealed conditions. The strips of CaO added AZ31 magnesium alloys were almost uniform in terms of microstructure and hardness.