针对现有海绵城市灰绿基础设施评价中碳足迹核算缺失及多目标协同不足的问题，本研究提出了基于博弈论的水-碳-经济全生命周期协同优化评价方法。通过构建“水环境-碳减排-经济成本”三维指标体系，集成径流总量削减率、污染物削减率、全生命周期碳排放及成本等关键指标，采用熵权法与层次分析法结合博弈论模型进行权重优化，以纳什均衡平衡目标冲突，并基于TOPSIS法实现多方案综合评价。以河北水利电力学院主校区为例，设计7种灰绿设施组合方案，结果表明：方案五（蓄水池、下凹式绿地、雨水桶组合）径流削减效果良好，污染物削减率均达到了48%以上，成本较低，碳汇显著，综合性能最优。研究解决了传统方法中“重技术轻协同”的局限，为海绵城市低碳化发展及“双碳”目标协同提供了理论支撑与实践路径。

[Objectives] Under the dual drivers of global climate change and rapid urbanization, urban flood disasters and water environment deterioration are becoming increasingly prominent, posing core challenges to sustainable development. Addressing the lack of carbon footprint accounting and insufficient multi-objective synergy in the evaluation of existing gray-green infrastructure in Sponge Cities, this study proposes a game theory-based life cycle synergistic optimization evaluation method for water-carbon-economy. [Methods] By investigating the synergistic relationships among water environment improvement, carbon emission reduction, and economic cost throughout the life cycle of gray-green infrastructure, a three-dimensional index system of "water environment - carbon reduction - economic cost" was constructed. This system integrates key indicators including runoff volume reduction rate, pollutant reduction rate, life cycle carbon emissions, and cost. Based on multi-source weighting and multi-criteria decision-making theory, the entropy weight method and the analytic hierarchy process (AHP) were combined with a game theory model for weight optimization. Nash equilibrium was used to balance objective conflicts, and the TOPSIS method was employed for the comprehensive evaluation of multiple schemes. [Results] Taking the main campus of Hebei University of Water Resources and Electric Engineering as a case study, seven gray-green facility combination schemes were designed. The results show that Scheme 5 (combination of storage tank, sunken green space, and rain barrel) achieved good runoff reduction, pollutant reduction rates above 48%, lower cost, and significant carbon sink effect, demonstrating optimal overall performance. The subsequent ranking of schemes was: Scheme 3, Scheme 7, Scheme 6, Scheme 1, Scheme 4, and Scheme 2. Sensitivity analysis confirmed that Scheme 5 exhibits good stability. [Conclusions] The case study analysis demonstrates that in the game theory-based comprehensive weighting model, the carbon emission indicator was assigned the highest weight. This significantly highlights the paramount importance of promoting low-carbon development goals within the current decision-making framework. Concurrently, the study also observed a significant divergence in the weighting results for the life cycle cost indicator between subjective and objective weighting methods. This profoundly reflects inherent differences stemming from distinct evaluation perspectives-namely expert judgment versus quantitative data. Notably, the advantage of the game theory model lies in its ability to effectively integrate and balance the contributions of these two methods through an equilibrium optimization mechanism, thereby significantly mitigating potential systemic biases inherent in single weighting methods. However, it is crucial to explicitly emphasize and state: Water environment indicators, such as runoff volume reduction rate and pollutant reduction rate, play a non-negotiable "bottom-line" role within the entire evaluation system. This means that in the active pursuit of low-carbon goals, the sacrifice of these critical water environment performance indicators is absolutely impermissible; the core requirements for water environment management must be rigidly satisfied. This research addresses the limitation of traditional methods that overemphasize technology at the expense of synergy, providing methodological support for the transformation and upgrading of Sponge Cities from "engineering compliance" to "synergistic benefits in water-carbon-economy". It delivers theoretical underpinning and practical pathways for the low-carbon development of Sponge Cities and their synergy with the "dual carbon" goals (carbon peaking and carbon neutrality).