Abstract Due to the fluctuation of electricity market price and intermittence of new energy generation, the demand for energy storage in the power system is also increasing. However, due to the high cost of energy storage construction and the long payback period of investment, users are not willing to build energy storage. Cloud energy storage is one of the development directions of energy storage in the future. This paper introduces the definition, characteristics and research status of cloud energy storage in detail, analyzes the relationship between cloud energy storage and distributed energy storage, summarizes the key technologies and business models of cloud energy storage, and prospects the future development of cloud energy storage.