With numerous policies of energy storage participating in the peak and frequency modulation service been released, it is necessary to make clear analysis about those policies.Firstly policies and cases of battery energy storage system(BESS) participating in the auxiliary service of peak and frequency modulation are summarized from the national, regional and provincial sides, combined with the frequency and peak modulation characteristics of BESS.The admittance requirement, compensation price and trading mode in typical provinces are summarized.Then, the compensation mechanism for BESS participating in frequency modulation service in the United States and Europe, as well as two compensation mechanisms in China are discussed, and the modes and mechanism of BESS participating in peak modulation in China are summarized, taking Qinghai province as an example.Finally, the existing problems of BESS participating in peak and frequency modulation under the existing policies are briefly analyzed.Suggestions related to those problems are put forward from the aspects of differential compensation, optimal allocation of frequency modulation resources, the mechanism of energy storage sharing and evaluation standard.