The South China Sea and surrounding areas (SCSSA) is one of the most sensitive regions with strong sea-land-air interactions. Extreme precipitation over the region has received widespread attentions in recent decades, because its large latent heat can exert substantial impacts on climate variability across the globe, through providing substantial energy and moisture for global atmospheric circulations. Utilizing gauge-based gridded data and a statistically downscaled CMIP6 dataset, we systematically investigate the historical and future spatiotemporal characteristics of maximum 1-day precipitation (RX1day), maximum 5-day precipitation (RX5day), very heavy precipitation days (R20) and very wet days (R95p) over this region. The RX1day, RX5day, R20, and R95p are commonly used to represent heavy rainfall, persistent heavy rainfall, high-frequency heavy rainfall, and accumulated heavy rainfall amount, respectively. Result shows that four indices share an analogous spatial pattern during 1951-2014 at annual and seasonal time scales, with large values appearing over Southeast Asia, the Southern China, and southern part of the Tibetan Plateau. That is, these regions are not only with heavy rainfall, but also manifest sustained and high-frequency heavy precipitation. The four indices show large values over Southeast Asia in four seasons, and depict great (small) values over South Asia, the Tibet Plateau, and East Asia in summer (winter). The projected four indices in the future maintain the historical spatial structures, and the four indices averaged over the whole region exhibit increasing trends during 2015-2100 under the SSP1-2.6 and the SSP5-8.5 scenarios. The percentage changes in the four indices during 2016-2035, 2046-2065, and 2080-2099 under two scenarios with respective to 1995-2014 exhibit slightly decrease in Southeast Asia and East Asia, and increase over South Asia and the Tibetan Plateau. In addition, the physical mechanism associated with extreme precipitation over Southeast Asia has been further explored. The cold sea surface temperature anomalies (SSTAs) over Indian Ocean, warm SSTAs over the tropical North Atlantic, and SSTAs over the tropical Pacific and Atlantic are responsible for southern dry and northern wet, overall wet, and northern dry and southern patterns of extreme precipitation over Southeast Asia, respectively.