In order to solve the problem of benefit sharing amount, a quantitative model was established, and a case study was conducted on the application of the model and the corresponding benefit distribution ideas. The results indicate that the stakeholders of hydropower development projects mainly include the central government, local governments, hydropower enterprises and reservoir immigrants, and the net present value method can be used to construct the benefit sharing model, in which the stakeholders take the product of the sum of the present value of net cash flows of hydropower projects and their input shares as the sharing amount. The grey prediction method was used to solve the model. The case of Xiluodu Hydropower Station proves its rationality. It is suggested to establish a development fund for immigrants and safeguard the interests of other parties to open up a new situation of co-construction and win-win of hydropower development.