Abstract: To meet the demand of fast response and lifesaving assistant decision-making,a model for buried personnel probabilty in an earthquake was established based on collapsing ratio and in-building probabilty by analyzing factors influencing the buried personnel probabilty.In this model,the in-building probabilty is used as the prior probability.By taking elementary and middle schools in the disaster areas in the Wenchuan earthquake as examples,the situation of buried personnel was explained with the established model,and its precision was analyzed with the error theory.The analysis result shows that the precision of the established model is about ±0.2.