Abstract: Based on the monthly west pacific subtropical high indexes in summer,the daily precipitation data in summer collected by 123 stations from 1961 to 2007 and the monthly NCEP/NCAR reanalysis data,the correlation coefficients between them and the features of drought-flood coexistence in the west and east of Sichuan-Chongqing basin in summer are studied.The results indicate that the correlation coefficients between the ridge,north boundary of West Pacific Subtropical High and drought and flood events in East Sichuan Basin,West Sichuan Basin is markedly.The anomaly latitudinal position of West Pacific Subtropical High has significant impact on the atmospheric circulation in East Asia and drought and flood events in East Sichuan Basin and West Sichuan Basin in summer.