Abstract: To build the risk evaluation system of ancient masonry pagodas under earthquake，vulnerability index was selected based on seismic properties and seismic damage investigation to plot fragility curve． Then it was built a mathematical model of earthquake risk by combining vulnerability analysis with seismic risk analysis，and also considering structural damage probability and seismic damage，which could quantify earthquake risk． With which the probability risk of Xiaoyan Tower was analysed and its risk value was calculated，so that it could be better protected．