Abstract: The paper deals with optimal operation of conjunctive-use system composed of reservoir and aquifer.Considering distributed parameter characteristic of the system,a general response function is used to couple physical model and optimization model,then a decomposition-coordination approach is established based on hiera rchical structure and complex in teractions of the system.Finally,the approach is applied to the reservoir-aquifer conjunctive use system in Xingtai distinct,and follows a satisfactory results.