Presented is classification of the starting times for late-spring to early summer floed rain in South Chiiia in the light of more objective analysis of long-term dataset,followed by examining the rainfall characteristics at the starting time,the difference in 500hPa mean circulation before and after the start and the circulation features in relation to different rainfall patterns.Evidence suggests that the mean circtilation undergoes marked change before and after,i.e.,the prestart circulation field favors the rise in temperature and humidity while the post-start field promotes cold air invasion into South China;at the beginning of the wet sea:on precipitation exhibits six dominant patterns,each corresponding to a particular circulation pattern;for different circulation situations moisture transfer and cold air display discrepancy in vigor,giving rise tto diversity of rainfall.