Abstract: With the increasing penetration level of renewable energy in new power systems, the stochastic nature of renewable energy significantly impacts the grid stability and reliability. Simultaneously, the extensive integration of power electronic devices has resulted in decreased damping and inertia within the power system. Due to the shortcomings, such as long starting time and low response rate, the traditional frequency regulation units have been incapable of meeting the frequency regulation needs of new power systems. Therefore, battery energy storage systems（BESS）, with their frequency support capability and fast response rate, have drawn considerable attention. The participation of BESS in the auxiliary market has also emerged as a key focus of research. The grid-connected control strategy of BESS is firstly presented, and then the research status of BESS providing primary and secondary frequency regulation services in power systems are analyzed.