Abstract: On the base of quality balance equation, the two-dunension ecological dynamic model is established, which could simulate the core process-ecological dynamic process of eutrophication in the water body with cxunplex boundary.Considering not only the hydrodynamic conditions but also the chemical, physical and ecological changes, the model gives the more detailed information of eutrophication.The model is used to describe the distributing situation of chlorophyll, total phosphorus and total nitrogen concentrations in the Geheyan reservoir.The results calculated by the model are consistent with the results monitored in the Gehevan reservoir.