Abstract:Aiming at the low production efficiention of traditional fixture in CNC machining, taking heavy truck front axle boring machining as the object, a fixture control system based on CNC system and PLC control was designed. The detailed design of the system were presented. The working process of M commands, and the signals flows of CNC,PMC,PLC, and PMC program and the PLC process were analyzes.The developed system is stable, the expected effect is is achieved, and the processing time is saved.