The gas generator generates continuous flow by fuel combustion in air. In order to guarantee the efficiency and stability of gas generator, the requirement of regulating speed and accuracy of air pressure is very high. The system use cascade control of pressure and position, bonding with fuzzy PID control strategy. The regulating speed is good and the control accuracy is very high by parameter optimization. The control accuracy of air pressure regulator valve position is more accurate than 0.2%. Between 1.5MPa to 5.8MPa, the regulating time of air pressure is less than one secondand the control error is less than 0.1 MPa .