Abstract: With the advent of the first retirement peak period of electric vehicle power battery, the subsequent treatment of used power battery is posing a serious challenge to the environment and social resources. The energy storage power station is an effective way for cascaded utilization of decommissioned power battery. It is of great practical significance to study the key technology and development status of decommissioned power battery cascaded utilization. In view of the main problems and technical difficulties faced by the battery cascaded utilization, this paper firstly introduces some echelon energy storage demonstration projects at home and abroad, and summarizes and combs the relevant policies and standards in the current industry.On this basis, the key technologies of battery classification, screening, reorganization, characteristics of the thermal runaway,equalization control and electrode material recovery in the process of cascaded utilization are studied, and the advantages and disadvantages of different methods and control strategies are emphatically analyzed. Finally, combining with the development trend of electric vehicles in China, the commercial application mode of battery cascaded utilization is discussed and prospected.