The dynamic model of the CNC cutting system was constructed by using the power bond graph method,and its dynamic characteristics were analyzed.〖KG-*3〗Based on MATLAB simulation,the key factors affecting the dynamic performance of the system were analyzed according to the simulation results.〖KG-*3〗The relationship between the motor current and the cutting force,the motor current and the feed rate was obtained.〖KG-*3〗The friction between the machining tool and the workpiece,the friction of the machine guide rail and the load were calculated.〖KG-*3〗The influence of the dynamic performance of the machine tool provides reference for the rational selection of the parameters of the CNC cutting system and the system optimization design.〖KG-*3〗Finally,the cam cutting force experiment was carried out to verify the accuracy of the established dynamic model of the CNC system and the feasibility of the method.