[Objective] The spatial-temporal variations of soil water erosion before and after the Wenchuan earthquake in the Baisha River basin of Dujiangyan City, Sichuan Province were assessed to support water source protection efforts and comprehensive control of soil erosion in the earthquake-stricken area.[Methods] The characteristics of soil water erosion (i. e., area, intensity, and spatial distribution) in the Baisha River basin from 2007 to 2020 were quantitatively analyzed by using the Chinese Soil Loss Equation (CSLE).[Results] ① The intensity of soil water erosion after the Wenchuan earthquake in the Baisha River basin initially increased and then decreased. The average soil erosion modulus values for the Baisha River asin were 817.51, 3 000.11, 5 828.89, 1 549.76, and 1 558.37 t/(km²·a) in 2007, 2008, 2013, 2018, and 2020, respectively. The intensity of soil erosion in 2020 was mainly classified as light erosion, and the average soil erosion modulus was 48.1% lower than in 2008. ② The average soil erosion modulus gradually increased with increasing slope gradient or altitude. Soil erosion amount contributed by regions with slope greater than 35° and elevation above 2 000 m accounted for 85.44% and 68.20%, respectively, of the total erosion amount in 2020. In addition, the extremely severe erosion area with an average soil erosion modulus of more than 5 000 t/(km²·a) mainly occurred in areas with elevation above 4 000 m. ③ Although the average vegetation coverage in the Baisha River basin in the past 10 years was between 60% and 74%, the proportion of the area classified as having moderate and more severe erosion was still greater than before the earthquake. In 2020, the proportion of moderate and more severe erosion area was 4.13 times greater than in 2007.[Conclusion] Even though the soil water erosion situation has effectively improved between 2013 and 2020, areas of intense and more severe erosion remain in the middle and upper reaches of the study area, and the topographic conditions and rainfall erosivity had an obvious impact on the change in erosion area.