Abstract: To solve the problems of automatic transmission, including the larger mass and volume of the multi-disc clutch hydraulic actuator, larger energy loss produced in solenoid valve, and to improve the traditional pressure control process in oscillation, precision and robustness, "motor & pump" direct control is often adopted to realize pressure regulation, taking its advantages of the simple structure, small mass and volume, and higher efficiency. Taking the pump-controlled actuator as the research object, a model-based nonlinear triple-step controller was proposed to control the internal pressure of the actuator. The results show that the proposed method can obviously improve the vibration of the actuator, the pressure control accuracy and time response.