Si-Mn alloy is an alloy composed of manganese, silicon, iron and a small amount of carbon and other elements. It is a kind of ferroalloy with wide application and large output. Its consumption occupies the second place in the electric furnace ferroalloy products, manganese and silicon in the manganese silicon alloy with a strong affinity with oxygen, in the use of manganese silicon alloy in steelmaking, the melting point of the deoxidized products MnSiO3 and Mn2SiO4 are 1270℃ and 1327℃, with low melting point, large particles, easy to float, good deoxidized effect and other advantages. Under the same conditions, the burning loss rates of manganese or silicon were 46% and 37%, respectively, while the burning loss rates of manganosilicate alloy were 29%.and can effectively shorten refining time and reduce refining power consumption. No smoke or flames during use, with good safety and environmental friendliness. Suitable for deoxidation in various forms of steelmaking, especially suitable for deoxidation in steelmaking and 3-5 kg per ton of steel. With strong deoxidation and desulfurization capabilities, it effectively improves the fluidity of molten steel, purifies it, reduces impurities in steel, significantly reduces steelmaking costs, and improves economic benefits.