[Objective] The dynamic changes of soil erosion in the mountain area of Southwestern Sichua Province were analyzed to support the comprehensive management of the regional ecological environment. [Methods] Based on the general soil loss equation, the study calculated the amount of soil erosion in the region from 2000 to 2018, and divided it into six levels including mild, light and moderate according to the national water erosion intensity grading standard. The spatial overlay analysis and linear regression equation methods were used to analyze its temporal and spatial changes. [Results] ① As a whole, soil erosion in the study area increased gradually from north to south. ② More than 50% of the region had obvious erosion. ③ In 2010, there was a obvious abrupt change in the intensity of regional soil erosion, but no significant change occurred in about 60% of the regional soil erosion intensity level over the whole period of time, and the overall stability of the soil erosion intensity levels was relatively high. ④ During the entire period, more than 95% of the areas in the region showed obvious improvement and no change in the degree of erosion state. [Conclusion] Soil erosion has been effectively controlled. The dynamic law of soil erosion in the study area is obvious, and rainfall erosion has an obvious driving effect on its change.