According to the current situation that the hydrologic data collecting system has rapidly developed in Zhejiang Province,a timely,accurate,visual and real time system,which can issue real time hydrologic information and forewarning,was designed and developed by using Browse/Server construction,and technology including ArcIMS,XMI,database,network and space-time visual.With the functions of inquiry,monitoring,issuing and forewarning,this system has provided a scientific,uniform and reliable platform for the governments at various levels in Zhejiang Province in flood control and drought relief decision making and commanding.