Abstract:CaO-Al2O3 based protective slag was prepared based on L25(65) orthogonal experiment. Influence of different components on physical and chemical properties of casting powder of high aluminum and manganese steel was studied and analyzed. The results show that melting temperature of molten slag of CaO-Al2O3-based castings powder drops with increase of different components. The sequence of influence on melting temperature is Li2O>Na2O>B2O3>BaO>CaF2>MgO. Content of each component within a certain range weakens viscosity of CaO-Al2O3-based continuous casting powder. Order of crystallinity of protective slag from difficulty to easiness is No.3, No.4, No.23, No.19, No.20, and No.5. Ca3B2O6, with low melting point, good glass formation and difficulty to crystallize, exists in most cooling precipitates calculated by thermodynamic software and meets the requirement of high aluminum and manganese steel continuous casting.