In order to improve the utilization rate of user energy storage and reduce the centralized energy storage configuration of micro-grid, a cloud energy storage capacity configuration method of aggregated user energy storage is proposed, and the pricing of energy storage transaction is studied theoretically. Cloud energy storage operator aggregate user energy storage and configure centralized energy storage at the same time. Cloud energy storage operator and users are regarded as an alliance to conduct external power trading, and individuals are encouraged to conduct energy storage capacity trading through aggregation fees and service fees within the alliance. Considering the respective interest demands of cloud energy storage operator, energy storage provider and energy storage demander, each subject model is established. In order to take into account the overall interests of the alliance and the individual interests within the alliance, an energy storage transaction pricing model aiming at maximizing the classical social welfare and Nash social welfare is established. The example results show that the method proposed in this paper can make full use of user energy storage, reduce the cost of centralized energy storage, and realize the maximum profit of the alliance and the profit balance of each subject.