Abstract: The design method of main circuit parameters, related control parameters and control strategy are systematically studied in order to promote practical application of 35 kV high-voltage large-capacity battery energy storage system (BESS). A simulation model of the 35 kV/10 MW/10 MWh system is built in MATLAB/Simulink to verify the correctness of the proposed design method and control strategy. The research results show that the 35 kV high-voltage BESS has large unit capacity and fast power response and can implement active state-of-charge balance and fault redundancy control of internal battery clusters. Its system efficiency and reliability are higher, which can adapt to the large-scale development of renewable energy in the future.