With the further development of energy storage and sharing economy, the operation mode of shared energy storage begins to be explored and paid attention to. In response to the problems of long investment and operation return cycles and low utilization efficiency in existing single energy storage scenarios, a shared energy storage investment and operation model is proposed mainly considering the three participants of shared energy storage operators, power grids, and users. Firstly, the operational models involving three parties are studied and analyzed, and a net profit model for shared energy storage operators, power grids, and users is established. Secondly, under certain profit conditions for the power grid and users, the goal of maximizing the revenue of shared energy storage operators is solved, and a mixed integer convex programming model is processed through quadratic fitting, M-envelope, and T-envelope methods. Then, to incentivize users to participate in energy storage, an improved Shapley value method is used to achieve partial grid delay benefit distribution among users. Finally, a simulation is conducted on three users in a certain region, and the Gurobi toolkit is applied to decide the investment and operation plan and service pricing of a shared energy storage operator, verifying the effectiveness of the investment and operation model.