Based on the "Project of East Lake Hydrology Network", a numerical model of diversion project of East Lake was established using MIKE21. A calibration of the model parameters (the bed resistance and the eddy viscosity) were performed by the water depth, the concentrations of total nitrogen and total phosphorus which were measured in East Lake in June and July in 2008. The hydrology model and the transport model are established by the measured value in East Lake in July, 2010. Four diversion conditions have been simulated. The distribution of total nitrogen and total phosphorus after 35 d' running have been established. Comparison of the simulated results of the four diversion conditions shows under the conditions of two inflows and considering both wind, the concentration, the distributions of total nitrogen and total phosphorus are the most uniform. This fining is important for the "Project of East Lake Hydrology Network".