Rainfall erosivity serves as an important indicator of soil erosion potential due to rainfall. Analyzing the long-term evolution of rainfall erosivity is significant for regional soil and water conservation planning and ecosystem management. This study used the daily rainfall data from 279 meteorological stations in the southern red soil region from 1982 to 2022 to analyze rain fall erosivity. The rainfall erosivity at each station was calculated using the Zhang model. The spatial-temporal variation trend, distribution characteristics and climatic and geographic drivers of the rainfall erosivity were analyzed using the Mann-Kendall test, the Kriging interpolation, the gravity model and GeoDetector. The results show that the annual average rainfall erosivity in the southern red soil region was 8786.95 MJ·mm·hm-2·h-1·a-1 from 1982-2022, exhibiting a significant upward trend. Seasonal rainfall erosivity was unevenly distributed, with approximately 50% occurring in summer, leading to the highest soil erosion risk due to rainfall. The annual rainfall erosivity in the southern red soil region ranged from 3,628.89 to 24,654.70 MJ·mm·hm-2·h-1·a-1 and showed an overall spatial trend of increasing from north to south. Most subregions (83.7%) also had an increasing annual rainfall erosivity. Erosive rainfall had a q-value of 0.872 and was the main driving force of the increase in rainfall erosivity in the southern red soil region. The number of erosive rainfall days, rainfall intensity and latitude were the secondary influencing factors, with a q-value of 0.504, 0.492 and 0.388, respectively. The q-value for the interaction between erosive rainfall and intensity was the highest (0.950). Geographical factors, such as latitude, longitude and elevation, showed different influences across regions. The variations in rainfall erosivity resulted from the combined effect of various factors. Due to the complex topography, exacerbated climate change and intense human activities, soil and water erosion remained a significant issue in the southern red soil region. Therefore, it is imperative to enhance soil and water conservation measures based on specific regional conditions. The findings can provide a reference for soil erosion forecast and management in the southern red soil area.