This paper proposes a new hydraulic rotary brake energy recovery system, which is designed to reduce the energy loss in large hydraulic excavator's rotary brake energy system, using accumulator recycling their swing braking phase of braking energy, secondary return when the rotation start releasing energy accumulator acting together with the variable displacement pump. It describes the similarities and differences between the two systems hydraulic principles established in AMESim model and simulation analysis. Simulation results show that: the new system on the one hand can reduce the power consumption and absorption system pressure variable pump fluctuations, on the other hand, the rotary brake energy recovery was 28.5%, recovery of braking energy recycling rate was 76.3%, the energy accumulator recycling rate of 21.7%, energy-saving effect, can effectively improve their energy consumption.