Abstract: Revealing the spatiotemporal variations in vegetation and the correlation with different factors provides a crucial basis for the quantitative assessment of regional ecological environment. Utilizing MODIS data from 2000 to 2020, we employed a pixel bipartite model to estimate fractional vegetation coverage (FVC) and analyzed the changes in vegetation coverage over the past 21 years in Sichuan Province. This analysis was conducted using the Sen+Mann-Kendall trend analysis, correlation coefficient method, and transfer matrix method, along with an exploration of the coupling changes with influencing factors. The results showed that: (1) The overall vegetation coverage in Sichuan Province was favorable, with medium to high coverage areas accounting for 85.31% of the total area. (2) Spatially, FVC was higher in eastern Sichuan than in the west, with lower coverage in the northwest and western regions, and higher coverage in the southern and northeastern parts. The overall growth and development status of vegetation were improved. (3) The correlations between temperature, precipitation, potential evapotranspiration, and FVC were significant in the central Sichuan Plain and northeastern regions. (4) There was a significant negative correlation between elevation and FVC across Sichuan Province. The elevation range with the highest average FVC was 1573-2302 m, with an average FVC value of 0.781. (5) Over the past 21 years, the areas of forest land, water bodies, unused land, and construction land had increased, while grassland and cultivated land had decreased. The conversion of cultivated land and grassland to construction land was the primary driver of FVC reduction. Overall, vegetation coverage in Sichuan Province showed an increasing trend from 2000 to 2020, with positive consequence on ecological environment improvement and protection.

Key words: fractional vegetation coverage, spatiotemporal variation, influencing factor, Sichuan Province