The treatment of lake and reservoir water bodies is not only an urgent need to improve ecological quality but also an important measure to achieve the strategies of green development and carbon neutrality. From the perspective of carbon reduction, this paper systematically analyzes the carbon emission characteristics in lake and reservoir water environment treatment technologies. Combining with an actual case of a park in Chongqing, it explores the comprehensive benefits of different treatment processes in terms of carbon emissions, costs, technical feasibility, and operation and maintenance expenses. Through the quantitative analysis of carbon emissions and treatment costs, and combined with the evaluation of technical feasibility and operation and maintenance, this paper proposes a comprehensive evaluation system for water environment treatment technologies from the perspective of carbon reduction, and verifies its comprehensive effect through the evaluation of different technical solutions in an actual engineering case. The research results show that water environment treatment requires a comprehensive evaluation of different treatment technologies. Only by achieving a balance among carbon reduction goals, economic benefits, and technical feasibility can the optimal path from the perspective of carbon reduction be reached, providing practical basis and theoretical support for the implementation of similar projects in the future.