In order to improve the accuracy of weights in the evaluation index system for the ecological revetment’s impact on river ecosystems, a combinatorial weighting method based on game theory was proposed. This method optimally combined the weights calculated by the analytic hierarchy process (AHP) and entropy weight method to obtain comprehensive weights, taking into account both the subjective judgments of experts and the objectivity of data. The case study of the Jiepai Water Conservancy Project of Xinmeng River in Jiangsu Province shows that the combinatorial weighting method based on game theory can reflect the characteristics of different weighting methods and obtain more reasonable evaluation results.