In order to improve the energy density of hydraulic accumulator and test the energy recovery performance of four assignment windows hydraulic pump prototype,AMESim was used to build up a physical simulation model of hydraulic flywheel accumulator and axial piston pump with four flow distribution window.Combined with the lifting model of heavy object and the lifting characteristics of hydraulic excavators arm,the related energy recovery hydraulic circuit was built,and the differential equation between the displacement of the variable pump and the velocity of the load was obtained.The energy density and energy recovery effect of the hydraulic flywheel accumulator were further analyzed by matching the parameters of static lifting working conditions of heavy objects.The simulation results show that compared with the common hydraulic accumulator under the same volume,the hydraulic flywheel accumulator can improve the energy storage density by 89.4% while taking into account the energy recovery efficiency;by using the obtained differential equation to control the swash plate angle of the pump,the jitter of the load can be reduced.