Abstract: Establishing a joint operation scheme for hydro junction projects is an important measure to lower the water pollution emergency risk of drinking water sources.In order to reduce the impact of the 2-MIB concentration seasonal boost in East Taihu Lake which may influence the water supply security of Jinze reservoir on Taipu River, by adopting a method coupling hydrodynamic model of the plain river network and mathematics regress analysis, and based on water situation in 2016,we carry out simulations on Taipu hydrojunction project discharging flow from 100 to 1000 m3/s and optimize the jointed operation strategy.It was detected that 800 m3/s and 400 m3/s were two key points that influence the flow arriving time to Jinze section and inflow ratio from both sides into Taipu River, and the limit range of 2-MIB concentration in streamflow of East Taihu Lake based on Jinze reservoir treatment ability was 525～1690 ng/L.Considering other influencing factors, we proposed a joint operation strategy for Jinze Reservoir and Taipu Hydrojunction Project under different combinations of 2-MIB concentrations in East Taihu Lake streamflow and discharges from Taipu Hydrojunction.The analysis can provide technical support for improving the water supply safety guarantee of Jinze Reservoir and provide a feasible reference for water supply scheduling in plain river network areas.