Abstract: Aiming at prevention of dam crashes, a kind of emergency accidents affecting the social public safety, the framework of the dynamic disaster appraisal system for defective reservoirs based on Web GIS technique is developed with the he present management the forecast appraisal S lp of the flood disaster appraisal techniques of ituation of reservoirs in China. Four steps of the the developed countries and considering the framework, i.e. the database establishment,, the real-time appraisal and the feedback appraisal of the disasters, are studied in detail.