Abstract: To investigate the status of ecological environment protection in the upper reaches of the Yangtze River, Yibin City, the first city on the Yangtze River known for its ecologically vulnerable environment, was selected as the study area to analyze the dynamic changes in vegetation growth over 20 years. Based on Landsat remote sensing data from 2001 to 2021, this study employed univariate linear regression analysis, coefficient of variation, spatial autocorrelation, and the Hurst index to analyze the spatio-temporal evolution trends of vegetation coverage in Yibin City. The Optimal Parameters-based Geographical Detector (OPGD) model was used to explore the driving forces. The results indicate that: (1) Areas with medium or higher grades of vegetation coverage accounted for 76.63% of Yibin City, indicating generally good vegetation conditions. Spatially, vegetation coverage showed a distribution pattern of "low in the northeast and high in other areas," while temporally, it exhibited a fluctuating downward trend. (2) Over the two decades, the study area showed a significant trend of vegetation degradation. Areas with a Hurst index greater than 0.5 accounted for 85.67% of the total, indicating a long-term positive persistence characteristic in vegetation change. The coupled analysis of Slope trend and Hurst persistence revealed that areas with persistent improvement in vegetation coverage accounted for 31.53%, whereas areas with persistent degradation accounted for 49.55%. The Moran’s I index showed high-high and low-low clustering, suggesting a significant trend of landscape patch fragmentation. (3) The OPGD detection results identified land use type, elevation, annual average temperature, and slope as the main driving factors for vegetation coverage change, with explanatory power (q-value) greater than 19%. The interaction of any two factors increased the impact on vegetation coverage change. The findings of this study provide a reference for promoting ecological environment protection, ecological restoration, and regional socio-economic sustainable development in the upper reaches of the Yangtze River.