Aiming at the problem of control interference and equipment loss caused by high frequency power electronic switching action when reconfigurable battery energy storage system participates in the frequency modulation process of power grid, a frequency modulation control strategy based on coordinated topology structure is proposed. Firstly, the operation control method of the reconfigurable battery energy storage system is designed to improve the cycle service life, flexibility and security of the battery energy storage system. Secondly, the virtual synchronous generator control is used to provide frequency modulation service. In order to reduce the influence of high-frequency power electronic switching, a reconfigurable battery energy storage system is proposed to participate in frequency modulation control strategy to ensure frequency stability. Finally, the effectiveness of the proposed control strategy is verified by simulation modeling.