Based on 176 meteorological hourly precipitation data over mainland of the South China (Guangdong and Guangxi) and monthly reanalysis data from ERA5 (European Centre for Medium-Range Weather Forecasts (ECMWF) fifth reanalysis) from 1981-2020, and applying the objective identification technique for regional extreme events (OITREE) and synthetic analysis, this study focused on the temporal and spatial characteristics of regional extreme precipitation event (REPE) over mainland of the South China, and further analyzed circulations in the years with high and low REPE frequency. The main conclusions are as follows. In frequency, the periodic variation of REPE frequency on the interannual scale is obvious, and it has obvious monthly distribution characteristics with the peak period from May to June. In extreme intensity and impacted area, the intensity of most REPEs in Guangdong and Guangxi is about 130 mm/d, and that of few events exceeds 320 mm/d, and the impacted area of REPEs shows a significant upward trend (~310 km2/yr). In comprehensive intensity, comprehensive index Z shows a significant upward trend (0.05/10 yr), which indicates intensity of REPE has a significant increasing trend. In the Greater Bay Area and northern Guangdong, the annual accumulated precipitation of REPEs and their contribution to annual total precipitation both show a significant upward trend, while in southern Guangxi, they show a downward trend. In addition, the circulations have obvious differences between the years with high and low REPE frequency.