The invention discloses a method for milling a step-shaped roller ring blank element by using a numerical control ring milling machine. The method comprises the following steps that materials are prepared according to the designed dimension; hammering upsetting is carried out, a primary blank is manufactured through punching; the primary blank is installed, a milling ring device of the numerical control ring milling machine is debugged, the milling ring device comprises a main roller, a core roller and an auxiliary roller, the rolling surface of the main roller is of a step structure matched with the step shape of the step-shaped roller ring blank element, the core roller is arranged in a center through hole of the primary blank in a penetrating way with a gap, and the auxiliary roller is positioned at the other end, relative to the main roller, of the primary blank, and comprises two cone rollers arranged at the upper end surface and the lower end surface of the primary blank; a numerical control program of the numerical control ring milling machine is started for milling and forming. The method has the advantages that the main roller of the step-shaped structure is used as a major component, the core roller and the main roller simultaneously act for milling the blank element, meanwhile, the symmetrical cone rollers are used for the auxiliary roller position limitation, the blank element of the step-shaped roller ring can be stably processed and formed, the working allowance of the blank element can be reduced, and the utilization rate of raw materials is improved.