Abstract: SiCp/Al composite is a typical difficult-to-machine material. Due to the presence of particle reinforcement in its matrix, it leads to poor machining quality, high cutting resistance, high machining damage and poor machinability under conventional cutting conditions. Conventional cutting can not meet the processing requirements. Through cutting simulation, the cutting process of composite materials, the damage characteristics of SiC particles, the surface morphology and subsurface damage of workpieces under conventional and ultrasonic vibration assisted cutting conditions are compared and analyzed. The results show that compared with conventional cutting, ultrasonic vibration assisted cutting can improve the surface integrity of the composite material, reduce the subsurface damage of the composite material, and improve the surface quality of the workpiece.