Comprehensive benefit evaluation is crucial to the planning, construction and management of groundwater reservoirs. In order to study the influence of the construction and operation of groundwater reservoirs on local water resources, ecological environment and social economy, an evaluation index system of groundwater reservoir comprehensive benefit is constructed from the overall perspective based on the discussion of the connotation of groundwater reservoir comprehensive benefit. Taking the proposed Fuping Groundwater Reservoir of Shichuan River in Shaanxi Province as an example, appropriate indexes are selected and the real-coded accelerated genetic algorithm is used to optimize the projection pursuit classification model. The comprehensive benefits of Fuping Groundwater Reservoir in Shichuan River are evaluated taking 2018 as the base year and 2030 as the planning year. The results show that the benefit of Fuping Groundwater Reservoir in Shichuan River is satisfactory, it still has good ecological maintenance value and water resource remediation effect in 2030, which indirectly demonstrates the feasibility of the construction of the proposed groundwater reservoir and provides important decision support for its subsequent planning, management and operation. The evaluation index system is feasible and can be widely used in comprehensive benefit evaluation of groundwater reservoirs.