The R style factor analysis is carried out for the summer rainfall fields of 16 observation station over Anhui Province from 1957 to 2000, by means of the factor load scatter diagram to carry out the division of observation stations to find the representative stations within the region, the summer rainfall statistical characteristics of the region, the long term trend of summer precipitation, the characteristics of regional droughts,and the inter decadal variation. The analysis indicates that the rainfall fields can be divided into 3 sub regions, in which Dangshan, 〖JP2〗Chuzhou and Ningguo can be used as their standard stations respectively. The results indicate that there is great difference in the characteristics of summer rainfall among the three regions for more than four decades. The summer rainfall in Zone 1 was the least, and that in Zone 3 was the greatest; there is most obvious difference between three zones in June; the long term trends of summer precipitation in Zone 1 and Zone 2 were not significant, but that in Zone 3 was very obvious. There were frequent droughts in Zone 1 from 1957 to 1970 and 1991 to 2000. The overall trends of the drought/flood occurrence frequencies in Zone 2 and Zone 3 varied over time, changing from droughts to floods.