Abstract: The decision support system (DSS) for water supply management in drainage basin integrates many functions, such as information of drainage basin, database management, rea-l time monitoring of regimen, flood forecasting, reservoir dispatch, calculation of crop's water demand, balance of water and land resources, optimum allocation and decision-making of water resources, system help on line etc. This DSS, which combines the natural conditions in Xinjiang arid area, and utilizes geographical information system (GIS), has many characteristics： (1) the better livetime; (2) agile and convenient operation; (3) friendly interface; (4) easy extension; (5) good practicability. It has the great directive significance and applied value in water supply, flood prevention, sediments removing in reservoir, irrigation in water saving and uniform management of water resources.

Key words: Water supply management, decision support system, GIS, optimum allocation of water supply