[Objective] Soil erosion in the Yellow River basin of Gansu Province was quantitatively analyzed and its driving mechanism was discussed in order to provide reference for soil and water resource management in this area. [Methods] The revised universal soil loss equation (RUSLE) model was used to quantify regional soil erosion in the Yellow River basin of Gansu Province from 1980 to 2020. The Theil-Sen slope was used to test the interannual variation of soil erosion, while spatial statistics were applied to determine soil erosion intensity and distribution under different underlying conditions. Additionally, geographical detector methods were used to investigate the main driving factors of soil erosion. [Results] ① The average soil erosion modulus (A) was 37.38 t/(hm²·yr) in the Yellow River basin of Gansu Province from 1980 to 2020, featuring an overall erosive intensity below the moderate level, with an area ratio of 70% to the total. Regionally, most of the Gannan Plateau was dominated by the slight level of erosion and presented a decreasing trend of A value during the statistical period. Longzhong and Longdong Loess Plateau were dominated by the light and moderate level of erosion, and both showed increasing trends. ② In terms of the land use/cover types, the highest A value and the largest amount of erosive volume were both found in the arable land, while the lowest A value and the smallest amount of the erosive volume were found in wetlands and the closed forest, respectively. Specifically, affected by the area of the distribution, in the Gannan Plateau, greater soil erosion was observed in the grassland, while in the Longzhong and Longdong Loess Plateau, remarkable erosion amounts were found in the arable lands. Topographically, higher A value was mainly located in zones with an altitude below 1 000 m above sea level, or within a slope range of 10° to 20°. ③ Mechanically, soil erosion was controlled and influenced more by the topographical factor of slope in the Gannan and Longdong Plateau, while soil erosion was significantly affected by soil texture in the Longzhong Plateau. The driving factors for soil erosion were multi-dimensional in tributary basins of Yellow River in Gansu Province, and the explanatory power of factor interaction was stronger than the explanatory power of individual factors regarding the variation of A value in space. High-risk zones for soil erosion were generally located in the steep terrain areas with greater precipitation and sparse vegetation. [Conclusion] The causes of soil erosion are different due to climate change and various underlying conditions. Serious soil erosion problems exist in Longzhong and Longdong loess plateau in tributary basins of the Yellow River in Gansu Province. In order to control regional soil erosion and facilitate better water and soil conservation, people should pay more attention to the improvement of land surface ecology in areas of rainfed farming land and grassland with low vegetation coverage.