The invention provides a closed-type pump-controlled hydraulic system. The closed-type pump-controlled hydraulic system comprises an alternating-current servo motor, a two-way metering pump, two overflow valves and a hydraulic cylinder; an output shaft of the alternating-current servo motor is connected to an input shaft of the two-way metering pump through a coupler; the two-way metering pump is provided with two oil pumping ports including the first oil pumping port and the second oil pumping port, and the two overflow valves are connected to the two oil pumping ports of the two-way metering pump in a crossing mode respectively and connected with the two-way metering pump in parallel; an oil inlet of one overflow valve is connected with the first oil pumping port, and an oil outlet of one overflow valve is connected with the second oil pumping port; an oil inlet of the other overflow valve is connected with the second oil pumping port, and an oil outlet of the other overflow valve is connected with the first oil pumping port; the first oil pumping port of the two-way metering pump is connected to a first cylinder oil port of the hydraulic cylinder through a first oil way, and the second oil pumping port of the two-way metering pump is connected to a second cylinder oil port of the hydraulic cylinder through a second oil way. Therefore, the purpose of saving energy can be achieved by adjusting the rotation speed of the alternating-current servo motor, such as lowering the rotation speed of the alternating-current servo motor.