Based on the analysis of the existing swing energy saving system of the hydraulic excavator and considering the swing working condition, a electrohydraulic swing braking energy recovery system of hydraulic excavator based on the accumulatormotorsupercapacitor is proposed. By adjusting the inlet pressure of the recovery hydraulic motor and rotation speed of the electric motor in realtime, the swing platform of the excavator can be braked smoothly. The hydraulic accumulator and supercapacitor is used to store the braking energy. The supercapacitor is used to compensates the nonlinearity of the hydraulic accumulator, by which the cost of energy storage unit is reduced. The mathematical model of the energy recovery system is constructed, and a cosimulation model of a 20ton hydraulic excavator with the energy recovery system is built. The energy recovery efficiency of the system and the operating characteristics of the swing platform are analyzed and studied under the noload condition. The results show that the system can achieve high efficiency recovery of swing braking energy without affecting the normal work of the system and operator’s operation habits. When the inlet pressure of the recovery hydraulic motor is set 23 MPa, the braking energy recovery efficiency can reach to 63.2%.