The potential energy recovery efficiency of asymmetric pump-controlled differential cylinder system was studied. Based on theoretical analysis, a mathematical model of potential energy recovery process was built, and the effect law of accumulator pressure on energy recovery efficiency was analyzed. The physical simulation model of potential energy recovery system was established and the potential energy recovery process was simulated. The results show that:compared with ordinary airbag type accumulators, using constant pressure accumulator can avoid the asymmetric pump from motor condition changing into pump condition then the residual energy in the process of potential energy recovery cannot be recovered;the maximum energy saving efficiency can reach 29.8% when the load is 10 kN.The optimal pressure curve of accumulator in the process of load falling was obtained through numerical analysis, which could provide theoretical guidance for the selection of accumulator for potential energy recovery.