Abstract: Based on the construction status and operational characteristics of the flash flood disaster prevention project in Jiangxi Province. This paper aims to scientifically evaluate the comprehensive benefits of the flash flood disaster prevention project. In light of local conditions, 29 assessment indicators in 7 aspects are determined. We combined the Analytic Hierarchy Process (AHP) and the Entropy Weight Method, introduced game theory, and used MATLAB to calculate the comprehensive weights of indicators. Using matter-element extension theory and the close value method, we constructed an evaluation model to comprehensively assess the status of flash flood disaster prevention in Jiangxi Province. The results show that the comprehensive benefit evaluation grades for Jiangxi's flash flood disaster prevention projects are Ⅲ, Ⅲ, Ⅱ, Ⅱ, Ⅱ and Ⅱ, with characteristic values of 3.43, 3.32, 2.47, 2.35, 2.17 and 2.03, respectively. These values exhibit a decreasing trend year by year, indicating that the projects are progressively yielding benefits. The characteristic values tend to stabilize several years after project implementation, which aligns with the typical timeframe of two to three years required for various engineering and nonengineering measures to be fully constructed and become effective. The evaluation results are consistent with the actual conditions of flash flood disaster prevention. This method can serve as a reference for evaluating the prevention benefits of flash flood disasters or other disasters in other regions.