Abstract: According to the existing standard data from DL/T787-2001, variations of 15CrMo steel were studied between the Mo element content of carbide, tensile strength, yields trength, elongation, reduction of area, hardness and temperature, spheroidization class. Meantime, the models of these variations were constructed and employed to predict the performance parameters of class 1.5,2.5,3.5 and 4.5. Besides, the models of evaluating 15CrMo steel spheroidization class were constructed according to tensile strength, yield strength, Brinell hardness and the Mo element content of carbide at room temperature. Computer could calculate the performance parameters and evaluate spheroidization class quickly by these models.