In the CNC machining process, the spiral bevel gear milling machine often has phenomena such as shock and oscillation, which seriously affect the machining accuracy of the gear. It is found that the nonlinear problem of backlash in the servo transmission system has a great influence on the machining accuracy, reliability and stability of the gear milling machine. By comparing the methods of eliminating backlash, a dual-motor backlash elimination method was proposed for gear milling machine transmission system based on PMAC motion controller. The basic principle of dual-motor backlash elimination and the process of eliminating backlash were analyzed, and the test process was designed according to the dual-motor backlash elimination principle; a dual-motor drive application system was built based on “IPC+PMAC motion controller”, and the relevant configuration was performed in PMAC IDE; finally, the experimental verification was carried out through the numerical control system test device based on the structure configuration of the upper and lower computers. The proposed method can effectively suppress the nonlinear interference and improve the stability of the system, the reliability of the proposed dual-motor servo anti-backlash scheme is proved.