Abstract: Based on the global climate model dataset BCC-CSM2-MR from the 6th Coupled Model Intercomparison Project Phase 6 (CMIP6) after downscaling, four forced scenario daily scale rainfall data were selected to analyze the spatiotemporal distribution characteristics of future rainfall in Wenchuan County, Sichuan Province, and simulate typical flood processes in the Shouxi River Basin in the future. The results indicate that the deviation corrected rainfall data has little difference from the observed data and can demonstrate the characteristics of future rainfall changes. The future rainfall of the four forcing scenarios shows an increasing trend, and the rainfall fluctuation under SSP3-7.0 scenario is the most severe, while the rainfall under SSP1- 2.6 scenario shows a stable upward trend, and the rainstorm center is located in the southeast of Wenchuan County. The future spatial pattern of rainfall in Wenchuan County is similar to history, with an increase in the average daily rainfall for both the near future (2015-2050) and the long term (2051-2100) in all four scenarios, and an expansion of the area with rainfall greater than 3.6 mm. SSP3-7.0 scenario has the highest peak flood discharge in the Shouxi River Basin, exceeding the design standard of a 100 year return period; The floods in the Shouxi River Basin have risen rapidly, with short convergence time, sharp peak, and short duration of peak; The duration of flood rise is 12~15 hours, and the range of flood rise rate is 0.16~0.43 m³/s²; The flood recedes slowly, with a subsidence rate ranging from 0.02 to 0.06 m³/s². The research results can provide reference for future flood disaster prevention and control in the Shouxi River Basin of Wenchuan County, Sichuan Province.