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 show that the coordinated use of multiple policies is conducive to the formation of a stable equilibrium in water-saving strategies; farmers are highly sensitive to water price changes, and increasing the water price for traditional irrigation is more effective in promoting their adoption of water-saving behaviors than reducing the cost of water-saving irrigation; water supply enterprises are more driven by long-term benefits, and the impact of subsidy policies is relatively limited; there is a substitution effect between government supervision and incentives, and relying solely on subsidies may lead to a lack of supervision.