Abstract: A multi-objective optimization model for ecological operation in Three Gorges cascade hydropower stations is proposed.The model considers the restrictive relationship between power generation and ecological restoration in Three Gorges,and balances the needs of competing interests of power generation and ecology.The objective functions are designed to maximize power generation while minimizing ecological water requirements,for which a multi-objective differential evolution (DE)algorithm is proposed.The evolutionary operators in the DE algorithm are modified according to the inherent nature of multi-objective optimization problems.A local chaotic search strategy is designed to perform multi-objective optimization,thus solving the problem of premature convergence in the DE algorithm.A non-penalty-based constraint handling algorithm is proposed to handle complicated problems in multi-objective optimization for ecological operation.The model is applied to the optimized ecological operation in Three Gorges cascade hydropower stations.The result demonstrates the effectiveness and practicality of the proposed model in engineering applications.