Abstract: To explore the temporal and spatial distribution characteristics of 24-hour extreme rainfall in different return periods and different rainfall frequencies in Sichuan Province, this study divided the hydrometeorological homogeneous regions of Sichuan Province by the regional L-moments method, then determined the best fitting curve, and the applicability of regional L-moments method in the west Sichuan Plateau were verified.Then we estimated the rainfall frequency values in different 24-hour recurrence periods of Sichuan Province, and its temporal and spatial distribution characteristics were analyzed.The results showed that:(1) Sichuan Province can be divided into 40 hydrometeorological homogeneous regions.The main fitting curves of Sichuan Province were determined as GLO,GEV,and GNO through conducting goodness-of-fit tests.GLO was the best-fitting curve in the West Sichuan Plateau.GEV was the best-fitting curve in most of the basin areas.(2) The regional L-moments method had good certain applicability to the western Sichuan plateau area where the stations were relatively sparse.(3) The spatial distribution of 24-hour rainfall extreme in Sichuan Province was significantly heterogeneous.Under the same return periods, the maximum value of the estimated rainfall frequency in different areas can be up to 10 times of the minimum value.