Based on the multi-source remote sensing raster data of hydro-meteorological conditions and the underlying surface characteristics, the study employed methods such as trend analysis and geographical detector to statistically analyze the spatiotemporal variation characteristics and driving factors of the runoff coefficient in the Karst Areas of Southern China from 1982 to 2022. The results show that: (1) the annual average runoff coefficient in the study showed an overall increasing trend, with an average annual growth rate of 0.0013/a, and the area with an increasing trend constitutes 89.6% of the study area. The runoff coefficient generally exhibits a lower value in the west and a higher value in the southeast. The increasing trend of the runoff coefficient becomes progressively significant(from P<0.05 to P<0.01). (2) Runoff coefficients in residential areas are significantly higher than those in other land-use types, with forested areas slightly surpassing grasslands. It is lower in karst areas than in non-karst areas, but more sensitive to changes in rainfall.(3) Climate factors play a more substantial role in controlling the spatial distribution of runoff coefficients than underlying surface factors. Precipitation emerges as the predominant factor influencing runoff coefficients in the region. The interaction of precipitation with temperature, vegetation coverage, elevation, and other factors has a significantly greater influence on the runoff coefficients compared to single factors. Due to the impact of vegetation restoration, the influence of vegetation coverage on the variation of the runoff coefficient in the study area is gradually increasing. The research results provide scientific support for the efficient utilization of water resource research in Southern Karst.