The feed servo system of CNC machine tool is a complex electromechanical coupling system. Due to the characteristics of time-varying parameters, load disturbances and motor nonlinear, it is difficult to model for the control system accurately. A fuzzy adaptive PID controller was designed based on the mathematical model of the CNC machine tool feed servo system. The controller was applied to control the feed servo system and better control performance was gained. The simulation results show that this method not only has no static distortion, but also has a fast response with little overshoot. This fuzzy adaptive PID controller has high stability and accuracy.