The invention provides a digital hydraulic actuator system for composite speed adjusting of a closed pump valve and a control method of the digital hydraulic actuator system. The system comprises a servo motor, a two-way quantitative hydraulic pump, high-speed switching valves, an energy accumulator, a hydraulic cylinder, pressure protection valves, a pressure sensor, a displacement sensor, a speed encoder, a motion controller and other elements. During work, the servo motor drives the two-way quantitative hydraulic pump to work, hydraulic cylinder reversing and system volume speed adjusting can be achieved, the high-speed switching valves can adjust and control the flow in the system, composite speed adjusting of the pump valve is achieved, the pressure protection valves are used for setting the safety pressure of the system and the maximum working pressure of the hydraulic cylinder, the energy accumulator achieves oil suction and drainage by storing and releasing oil, the characteristic that the flow of an asymmetric cylinder is not balanced is overcome, the high-speed switching valves on an oil inflow way in the system can be used as load holding valves in a switched-off state,the hydraulic cylinder can be positioned, and the motion controller can control actions of all the elements after processing signals. The digital hydraulic actuator system for composite speed adjusting of the closed pump valve and the control method of the digital hydraulic actuator system have the beneficial effects of being flexible in control, high in precision, rapid in response, remarkable inenergy-saving effect, high in safety and the like.