The invention relates to a hybrid energy storage topological structure on the basis of an MMC (modular multilevel converter). The structure comprises a positive bridge arm and a negative bridge arm; the positive bridge arm is formed by sequentially connecting power conversion subunits 1 to n in series; one end of the positive bridge arm is connected with a high-voltage DC (Direct Current) positive bus bar and the other end of the positive bridge arm is connected to a high-voltage three-phase AC (Alternating Current) power grid by a current limiting reactor; the negative bridge arm is formed by sequentially connecting power conversion subunits n+1 to 2n in series; one end of the negative bridge arm is connected with a high-voltage DC negative bus bar and the other end of the negative bridge arm is connected to the high-voltage three-phase AC power grid by a current limiting reactor; each functional conversion subunit is formed by connecting a power conversion module, a potential isolation module and an energy storage module in series. According to the invention, various energy storage bodies are flexibly switched into a power system and an energy storage function and a service which are uninterrupted, high in quality, flexible to control and safe to operate are provided for the power system.