Abstract: Using the advanced geographic information issuance system ARCIMS and network techniques, a basic architecture for flood control and dispatch information system of Yangtze River's middle and lower reaches is proposed. On the basis of handling the electronic data map and building the GIS database, applying Web GIS can achieve the real-time queries and transfers of hydrologic messages, reservoir messages, dike messages, flood diversion area messages, dispatch messages, etc., on map. At the same time, through showing on the Yangtze River flood dispatch alteratives intuitively by the computer cartoon, all these may help experts to make the decision correctly and quickly during the flood period.