The diagnostic analysis of 500hPa circulation features of the exceptional high temperature in summer 2003 in Jiangxi Province shows that the exceptionally strong subtropical high was the main cause responsible for the high temperature.After generally investigating the correlation of summer high temperature in Jiangxi with the 500hPa height fields and SST fields from 1959 to 2002,and comparing the composites of 500hPa height and SSTA of high and low summer temperature years,it is found that the positive SSTA in the equatoral central-east Pacific in the previous October and the negative height anomaly around Novaja Zeml’a in January have a close relation to summer high temperature especialy,the SSTA in the previous October has a good relationship with the subtropical high in the subsequent summer.