A PID control system was designed in order to improve the control effect of pressure stabilized vacuum hot pressing machine.Through algorithm optimization control,the function of effective pressure con-trol of vacuum hot pressing device is achieved,and the joint control of system speed and pressure is effec-tively achieved.The experimental results show that when the errors of position and pressure are both within 0.1%,the pressure control accuracy of 99%can be achieved,and the position accuracy of 99.3%can be obtained.The pre-loading position can reach the set target after 20 seconds,and maintain a stable law of applying load.The target pressure can reach the set target after 12s,and the overshoot is in a controllable range.The research is helpful to improve the control efficiency of hot pressing machine and lay a theoreti-cal foundation for the optimization of loading process.