Abstract: Taihu Basin suffered rare high temperature and drought in 2022, and the Chenhang Reservoir in Shanghai City was threatened by severe salinity intrusion. Based on the forecasting and dispatching integration system of Taihu Lake Basin, the coupled one-dimensional(1-D) water quantity of river network, the two-dimensional(2-D) quality model of the Taihu Lake, and the incoming water composition model were driven, in order to realize the simulation, analysis, forecast, and risk warning of water level, discharge, and incoming water composition under different spatial scales (watershed, region, town), multi-factor (river, lake, reservoir, sea), engineering group (sluice, pumping station, etc.) and different scheduling rules (discharge, regulation, capacity scheduling). The research findings were applied to the planning of the emergency water supply route for the Chenhang Reservoir. The research results showed that more than 60 numerical simulation and rehearsal of the flow movement tracks of main rivers for water replenishment were evaluated. Furthermore, the First North, Second North, and South water replenishment route were proposed, among which the First North water replenishment route had higher efficiency and was basically consistent with the real situation. The research solved the water supply difficulties of the Chenhang Reservoir which could only maintain for 5 days, and provided important references for the multi-objective coordinated scheduling of watersheds and regions and guaranteeing the safety of water supply.