Substations are important hubs for transmitting electricity in power grids, and the assessment of their flood control capabilities is crucial for improving flood warning systems of power grids. However, factors affecting the static flood control of substations are complex, and the assessment process is highly subjective and fuzzy, which poses difficulties for static evaluation. To solve this problem, a static flood control capability evaluation index system of substations is constructed, and then a fuzzy comprehensive evaluation algorithm for the static flood control capability of substations based on combination weighting is proposed. The algorithm uses game theory to combine the analytic hierarchy process and entropy weight method to weigh the evaluation indicators and finally adopts the fuzzy comprehensive evaluation method to obtain the evaluation results. The experimental results show that the game theory-based combination weighting method can balance the subjective analysis of the analytic hierarchy process and the objective analysis of the entropy weight method well, and the calculation results are consistent with the flood disaster causation mechanism. The fuzzy comprehensive evaluation method proposed in this paper is reasonable and effective, with high confidence in the conclusions, and it can provide reference and decision-making assistance for actual flood warnings of substations.