Abstract: To enhance the water-saving efficiency in the agricultural sector of plateau lake areas and promote the optimization of water pricing mechanisms, taking Chengjiang City in Yunnan Province as an example, a tripartite evolutionary game model involving the government, water supply enterprises, and farmers was constructed. The behavioral evolution paths of each subject under the influence of policy tools such as subsidies, penalties, and water price adjustments were analyzed, and the stable strategies of the system were numerically simulated using Matlab. The results showed that, the coordinated use of multiple policies was conducive to the formation of a stable equilibrium in water-saving strategies; farmers were highly sensitive to water price changes, and increasing the water price for traditional irrigation was more effective in promoting their adoption of water-saving behaviors than reducing the cost of water-saving irrigation; water supply enterprises were more driven by long-term benefits, and the impact of subsidy policies was relatively limited; there was a substitution effect between government supervision and incentives, and relying solely on subsidies may lead to a lack of supervision.