The invention provides a method for reducing the throttle loss of a hydraulic system. A hydraulic control system comprises a hydraulic cylinder, one-way throttle valves, servo slide valves, hydraulic control one-way valves, a variable hydraulic pump, a quantitative hydraulic motor, reversing valves, a shuttle valve, damp holes, a pressure oil pipeline and an oil return pipeline. When the reversing valve I is located in the right position, a piston rod of the hydraulic rod extends out, when the pressure difference of the two ends of the one-way throttle valve I is higher than or lower than the set value P0 of the servo slide valve II, the servo slide valve II and the variable hydraulic pump are controlled by the pressure difference of the two ends of the one-way throttle valve I, the rotation speed of the quantitative hydraulic motor and the flow of the one-way throttle valve I are adjusted, the pressure difference of the two ends of the one-way throttle valve I is equal to P0, and the servo slide valve II does not act and enters the stable state. The reversing valve I is located in the left position, the servo slide valve I and the variable hydraulic pump II are controlled by the pressure difference of the two ends of the one-way throttle valve II, the rotation speed of the quantitative hydraulic motor is adjusted, and the flow of the one-way throttle valve II is constant. By the adoption of the method for reducing the throttle loss of the hydraulic system, the throttle loss generated in the speed governing process of the hydraulic system can be lowered effectively, the energy is saved greatly, and the service life of oil liquid is prolonged.