The invention provides a nitrated silicon-manganese alloy and its melting process, which includes the following steps: material getting, forevacuum, nitrogen melting, pressure keeping at constant temperature, clamp dog adglutinating and so on. The percentage by weight of chemical composition of the produced nitrated silicon-manganese alloy product is as follows: 55-70% Mn, 13-20% Si, 9-15% N, 1-2% C, and the other is iron and inevitable impurity, of which the density is 6.1t / m3, and the alloy could be used as additive for smelting 20 manganese-silicon low-alloy steel or steel species including bar above HRB400 level and can quickly immerse into the liquid steel and sufficiently contact with the liquid steel, the absorption and availability ratio of the pivot element including manganese and silicon can arrive at more than 85%, the alloy can reinforce the solid-melting forced characteristic of the steel and can reduce the cost, and can substitute the current additive series raw materials and simplify the species and metallurgy species of the purchased and stored steel-smelting raw materials, is suitable for organization of production and business administration, can reduce the managerial operation cost, which has great economic benefit and environmental benefit and good extension and operation foreground.