Abstract: The stability, dynamic performance, and steady-state performance of the CNC milling machine control system are key factors affecting machining accuracy. This paper presents a SIMULINK simulation analysis of the original photoelectric tracking control system of a CNC milling machine. Addressing its performance shortcomings, three improvement schemes based on PID correction are proposed, and a fully digital system simulation is performed using MATLAB modeling. Through comparative analysis of the simulation results, a reasonable system optimization scheme is proposed, and the optimal optimization parameters K_P, T_I, and T_D are finally determined, thereby improving the performance of the control system. Keywords: servo system; system model; performance; system simulation; optimization scheme Abstract: The stability, dynamic and steady-state performance of a numerically controlled system are important factors affecting product accuracy. In this treatise, simulation of an initial photo-electronic tracking servo system reveals its performance disadvantages, and three optimization schemes based on a PID controller are designed to improve the overall control system. After composing and simulating the three new models using MATLAB, the simulation results are analyzed to determine the optimal optimization parameters for function enhancement. Keywords: servo system, system model, performance, system simulation, optimization scheme 1 Introduction CNC milling machines are modern production equipment integrating optical technology, laser technology, computer technology, information processing, control technology, and other disciplines. Modern control theory and technology are its theoretical foundation and technical support. As an important component of the CNC milling machine control system, the performance of the photoelectric tracking servo system directly affects its working performance and machining accuracy. As modern CNC milling machines continue to develop towards higher speeds, higher efficiency, and higher precision, the requirements for servo systems are also increasing. Optimizing existing servo systems can meet these ever-increasing demands and also provides a reference for selecting optimization schemes and adjusting parameters for similar control systems. For details, please click: Simulation and Optimization Research of Photoelectric Tracking Servo System for CNC Milling Machines