This paper makes analysis and application research of the buildings vulnerability and the citizens′ potential life safety.During the analysis process the unpredictable economic loss and residents′ safety caused by building vulnerability also discussed.The earthquake disaster analysis database is established using the GIS（geographic information system） technique

and combined with the system for disaster prevention and mitigation based on the GIS-tech.Firstly relevant building vulnerability analysis database is constructed

by the analysis of building vulnerability（mainly including building structure

height

area

cost and so forth）.Then combing building earthquake disaster loss assessment model and casualty forecast method

we complete the economic loss evaluating and casualty foreseeing

which is based on the various constructions of buildings in different conditions of seismic intensity.Finally

an urban disaster prevention and mitigation decision support system is built.The object is to achieve a more scientific and accurate assistant decision making programming for urban disaster prevention and mitigation.