In the context of the daily precipitation data of 60 stations in Jiangsu from 1961 to 1999 and the daily reanalysis wind field data from NCEP/NCAR,the spatial-temporal variation characters of precipitation in Jiangsu and the background of atmosphere general circulation during 1st-7th May are analyzed.Results indicate that the temporal variation characters of precipitation are related to the course of summer monsoon onset in the South China Sea;and Jiangsu can be divided into the southern and northern areas of precipitation variation.The distributive characters of precipitation and 850hPa wind field are also analyzed in the year when the extreme precipitation occurred in Jiangsu during 1st-7th May,and it is found that the precipitation lay obviously north of the climatological normal and the subtropical high of the west percific appeared obviously abnormal in the extreme year.