The invention relates to the fast machine steel containing elements of calcium, sulfur and magnesium belonging to the area of metal material. The invented material can be utilized to manufacture important parts such as crankshafts and connecting rods applied in automobiles. Measures are taken such as the neutral covering dregs, diffusion deoxidation, deoxidation by use of feeding wire, deteroprating the encrusting matter by use of the elements of calcium, sulfur and magnesium etc. to produce the steel with both of good mechanical and fast machine properties. The mechanical properties of steels Y45CaSMg, Y45CaSMg are as following: the tensile strength as 800 MPa for sample in hot rolling state, the extensibility as 17.7% and the contraction of area as 47%.