Aimed at the stability requirement of busbar voltage in DC microgrid and the performance defect of the battery,the hybrid energy storage system combined super capacitor with battery organically is used；The structure of the hybrid energy storage system is analyzed to improve the performance of energy storage system and the response speed and impact resistance；the output characteristic of the hybrid energy storage system is designed to control bus voltage effectively in the state of island mode,The system simulation model is built in the matlab / simulink,which analyzes the microgrid interconnection,turn island operation,the simulation results show the effectiveness of the hybrid energy storage system．