Abstract: The paper aims to master the background of general atmospheric circulation and features of physical quantity allocation of regional rainstorm in flood season in the south areas of Huai River, Anhui Province, and provide favorable reference for regional rainstorm forecast. The author analyzed 171 typical cases of regional rainstorm from May to September in the south areas of Huai River, Anhui Province in 1960-2013 based on composite analysis, EOF decomposition, significant difference tests and correlation analysis, and mainly analyzed spatial and temporal distribution, large-scale circulation type and distribution characteristics of physical quantity field. The results showed that: large scale circulation features of regional rainstorm in the south areas of Huai River, Anhui Province marked by a two ridges-one trough in the high latitude to the south of the Huai River regional rainstorm large-scale circulation feature mainly for the black mountain near the highly significant positive abnormal strengthening, prompting the cold air from the north along the ridge of the northerly flow south, mid high latitude showed two ridge one trough. Heavy rain was caused by the convergence of three flows in the vertical direction: the southerly jet in the boundary layer, southwest jet in the low level and westerly jet. The rainstorm area was often located in north to the south Asian high, to south of upper westerly jet, and the left front of the low-level jet, the left side of the boundary layer jet, and south to the warm shear in the 850 hPa level, positive and negative moist potential vorticity were overlapped in the vertical direction. Unstable stratification condition was thus favorable for heavy precipitation.