Quantitative assessment of the stability of reservoir bank is a complicated systematic engineering as the selection of evaluation index and the establishment of evaluation system are based on qualitative cognition ； while the relevance and independence between evaluation factors and reservoir bank are reflected by mathematical indicators including weights and the degree of membership. In this paper, fuzzy comprehensive evaluation is used to evaluate a 72.4 km long reservoir bank of a hydropower station. Being consistent with the results of site survey and remote sensing, the evaluation results are highly valuable.