Based on the daily precipitation data of flood season in 1961-2006 from 145 stations over Sichuan Basin, we analyzed the temporal and spatial variations of extreme precipitation events. Results indicate that the extreme precipitation event frequency of flood season shows a gradual decreasing trend from west to east, which is remarkably different from the precipitation distribution. The anti-phase changes between Western Sichuan Plateau and Sichuan Basin, as well as west and east Sichuan Basin, are the main spatial models of extreme precipitation event frequency in flood season. The spatial distribution of extreme precipitation event frequency in flood season over Sichuan Basin can be identified into eight regions: central Sichuan Basin, east Sichuan Basin, south Sichuan Basin, west Sichuan Basin, west of Western Sichuan Plateau, central Western Sichuan Plateau, southwest Sichuan and east Chongqing. In terms of long-term trend, there is an apparent linear trend in extreme precipitation event frequency for all the regions, with the exception of a slight decrease and increase for west Sichuan Basin and east Chongqing. Among the eight regions, east Sichuan Basin, southwest Sichuan, western and central parts of Western Sichuan Plateau show an increasing trend, whileas central and southern Sichuan Basin show a decreasing trend. The fluctuating West Pacific Subtropical High and the varying intensities of East and South Asian monsoons have significant impact on extreme precipitation events over eastern, central and western parts of Sichuan Basin, respectively.