[Objective] The characteristics and spatial variation of soil erosion in karst plateau mountainous areas were investigated, in order to provide scientific basis for the prevention and control of soil erosion in accordance with the environment of karst mountainous areas.[Methods] Libo County of Guizhou Province, a key ecological function area in typical karst mountainous area, was taken as the research area. The spatial distribution of topographic relief and soil erosion sensitivity and their relationship were analysed by ggeospatial analysis method, to determine the best analysis unit for extracting topographic fluctuation degree, and the evaluation method of soil erosion sensitivity.[Results] Based on DEM data with 10 m spatial resolution, the optimal grid size for extracting topographic relief was 54×54, and relief degree of land surface(RDLS) was between 0.32 and 2.12. The sensitivity of soil erosion in Libo County was mainly slight erosion, which accounted for 88.40% of the total area of the county. In addition, the sensitive area of soil erosion was mainly concentrated in the RDLS range of 0.7~1.7. The RDLS ranged from 1 to 1.5 was the most sensitive response to soil erosion, and thus the dominant factor range of soil erosion sensitivity.[Conclusion] The distribution of RDLS in the study area was consistent with that of soil erosion with different sensitivities. Generally, soil erosion was significantly affected by the change of topographic relief.