Abstract: Renewable energy generation has a strong random and intermittent nature, which poses a great challenge to power system operation and control. Energy storage is one of the most important means to solve this problem. This paper focuses on the new background of zero-carbon park and the new economic model of shared energy storage, and conducts a study on the optimal dispatch and economic evaluation of zero-carbon park considering the capacity attenuation of shared energy storage. Firstly, the cost-benefit model of zero-carbon park is established, which takes the operation cost as the optimization objective. Then, an economic evaluation index of shared energy storage is put forward. Afterwards, three allocation options, namely, no energy storage, self-assigned energy storage and shared energy storage, and two battery options, namely, new battery and retired battery, are considered in the case study. The results of optimal dispatch and economic evaluation are compared with different options. Finally, the impact of shared energy storage service price on its economy is highlighted through sensitivity analysis, and the suggested values of service price are given. The results of the example verify that the economy of the shared energy storage is superior to other schemes. In addition, although the performance of retired batteries is lower than that of new batteries, the cost is far lower than new batteries, so the economy of retired batteries participating in this study case is better.