[Objective] The regional characteristics of rainfall erodibility in karst ecologically fragile areas were studied in order to provide scientific reference for soil erosion prevention and eco-environment protection.[Methods] Long-term (1960-2017) daily precipitation data from 33 meteorological stations were assembled to analyze the spatial and temporal variations of rainfall erosivity in different river systems of Guizhou Province, and the spatial interpolation, linear trend, gravity model, mutation test, and cluster analysis methods were used.[Results] The rainfall erosivity of the eight river systems mainly showed a fluctuating downward trend, which was consistent with the regional variation trend based on the cluster division, but an abrupt change was not obvious. The spatial variability of rainfall erosion was great. The spatial distribution of rainfall erosivity in the Yangtze River basin decreased from southeast to northwest, while that in the Pearl River basin increased from east to west. Heavy rain was closely related to rainfall erosivity because the migration path of the gravity center was similar to that of rainfall erosivity, and the gravity centers were mainly concentrated in Guiyang City and its surrounding areas. Most of the river systems showed a significant correlation (p<0.05) between rainfall erosivity and longitude, latitude, altitude, and slope, but the correlation with aspect was not obvious.[Conclusion] The spatiotemporal variability of rainfall erodibility in various water systems in Guizhou Province is strong, and the regional characteristics are obvious. Soil erosion control should be carried out in karst ecologically fragile areas according to regional characteristics.