Abstract: Marine ranching is a crucial strategy for advancing marine fisheries, as it serves the dual purposes of habitat restoration and resource enhancement. However, the comprehensive evaluation of the construction effectiveness of marine ranching represents a crucial technical challenge within the realm of marine ranching development. Evaluating the impact of marine ranching involves a range of factors such as fishery resources, phytoplankton, zooplankton, the marine environment, and the implementation of artificial reefs, each presenting challenges due to their complex and often non-quantifiable nature. The fuzzy comprehensive evaluation method is a mathematical analysis approach that converts uncertain and vague elements into quantitative expressions using membership functions. This method is particularly effective in handling the inherent vagueness of evaluation index attributes, providing a practical means for the comprehensive assessment of entities or objects influenced by multiple factors. We established an evaluative index system for marine ranching in fishery resources conservation, encompassing four key aspects: achievement of engineering goals, impact on fishery resources conservation, influence on biological community conservation, and effect on marine environment protection. A comprehensive evaluation model for marine ranching in fishery resources conservation was formulated. Utilizing Miaowan marine ranching in the estuary of the Pearl River as a case study, the results indicate that the conservation of fishery resources through marine ranching in Miaowan is favorable, with an evaluative value of 0.7462. Notably, the achievement of engineering goals contributes 38.95%, the impact on fishery resources conservation contributes 29.91%, while the effect on biological community conservation and marine environment protection account for 18.75% and 12.39%, respectively. The proposed index system and methodologies in this study are comprehensive and practicable, offering feasible means of index acquisition with clear and interpretable results. This research presents technical approaches for the comprehensive evaluation of marine ranching in fishery resource conservation, and the application of these methods is anticipated to enhance the management efficacy of marine ranching for fishery resource conservation.