In order to improve the anti-interference ability of the feed system control system of CNC machine tools and reduce motion trajectory tracking errors, a SMC-PI（Sliding Mode Controller Proportional Integral）control method was designed, and the motion displacement, speed, and acceleration of the feed system were simulated. A schematic diagram of the CNC machine tool feed system is provided, and its working principle is introduced. A SMC-PI control method for CNC machine tool feed system was designed by combining sliding mode control system with PI control system. The stability of the SMC-PI control system was demonstrated by using the Lyapunov function, which enhances the anti-interference ability of the CNC machine tool feed system control system. Taking different external environments as examples, Matlab software is used to simulate the motion displacement, velocity, and acceleration of the feed system. The results show that in a non-interference external environment, based on traditional PID control and SMC-PI control methods, the tracking errors of displacement, speed, and acceleration in the machine tool feed system are not significantly different. In environments with interference, the SMC-PI control method is significantly superior to traditional PID control, and the tracking errors of motion displacement, speed, and acceleration in the machine tool feed system are relatively small. The use of SMC-PI control method can improve the tracking accuracy of the motion trajectory of the CNC machine tool feed system, and has anti-interference ability.