“Under the influence of global climate change and human activities, floods and waterlogging disasters have occurred frequently in the Xijiang River Basin, and the runoff sequence has significantly changed. The study used Mann Kendall mutation test and univariate linear regression methods to reveal the non consistent characteristics of runoff sequences in the watershed. Based on CMIP6 climate model data, the BCSD downscaling method was used to drive the XAJ hydrological model, revealing the future changes in water resources in the watershed. The research results provide important scientific basis for the rational planning, allocation, and utilization of water resources in the basin.”