Unit selection is the key step in the process of hydropower station efficiency and capacity expansion, and its impact on the economic benefits after the transformation is fundamental. For hydraulic turbines with similar performance, the traditional selection and comparison method is difficult to distinguish between advantages and disadvantages. In order to better solve the problem of selection of hydraulic turbine units with similar performance, this paper adopts the dynamic simulation method, that is, by setting the technical and economic target parameter and the decision variable containing the unit characteristic parameter, the different is matched with the objective hydrological process, and the intelligent algorithm is used to optimize. When is obtained, the unit corresponding to the optimal solution is the selected unit. Taking Shankou hydropower station as an example, the superiority of dynamic simulation method is illustrated. This method can be used for reference in similar projects.