Flood is the disaster most frequently occurring every year in China. How to monitor and evaluate the flood assures the objectivity￡?accuracy and efficiency by new technologies￡?It?ˉs the most urgent problem for Chinese government and experts to deal with. The Institute of Remote Sensing Applications of CAS and China State Information Center have developed Network-Based Flood Disaster?ˉs Monitoring and Evaluating System Using Remote Sensing and GIS. The system includes three parts￡o 1. Flood Disaster Information Generation subsystem 2. Flood Disaster Information Service subsystem 3. Network User subsystem This System has been applicated in monitoring and evaluating flood disasters in China during 1997?a1999. It plays an important role in flood control and disaster mitigation￡?especially in floods occruing along Yangtze￡?Songhua and Nen Rivers in 1998. Up to now￡?131 flood information reports with flood images￡?maps and tables for the flooded areas are provided to the State Council￡?relevant ministries and provincial governments. User can browse￡?query and download the flood information through Internet by permission. This paper introduces the work environment￡?the flow of key techniques and its methodology of the system￡?and gives some application examples.