The Yangtze River Delta,which is composed of Shanghai,southern Jiangsu province and northern Zhejiang province,is one of the most prone areas to typhoon disaster in China for its specific geographical position.Considering both hazard and vulnerability,this paper assesses the typhoon disaster risk concerning 140 counties in the Yangtze River Delta.10 indices are used to evaluate the typhoon hazard index using a principal component analysis method.They include:annual average precipitation caused by typhoon,average ground win.d speed caused by typhoon,number of days with total precipitations more than 50mm,100mm,200mm,and number of days with ground wind speeds higher than 10.8m/s,13.9m/s,17.2m/s,20.8m/s,24.5m/s.Similarly,3 indices are chosen to evaluate the counties vulnerability index:GDP,population density,and the percentage of primary industry product in 2006.