[Objective] The spatial and temporal properties of vegetation cover in the Hengduan Mountains and the variables that influence them was investigated in order to provide the scientific basis to understand this topic. [Methods] The Theil-Sen trend analysis and Mann-Kendall test were used to analyse the inter-monthly and inter-annual variability of the normalized difference vegetation index (NDVI) in the Hengduan mountains from 2002 to 2022, as well as spatially overall. Using partial correlation analysis, the effects of temperature and precipitation on vegetation cover were examined. Finally, the impact of human activities on vegetation cover was explored combining with land cover data. [Results] ① The NDVI in the Hengduan mountains area showed an increasing fluctuating trend over 21 years, at its lowest in March and highest in September. ② The spatial vegetation cover increased by 83.78%, primarily in the southeastern, southwestern, and northern regions, and decreased by 15.87%, primarily in the central, southern, northwestern, and northeastern regions, with a good trend of increasing vegetation cover throughout the study area. ③ The NDVI showed a strong positive correlation with both temperature and precipitation on the monthly scale, while on the annual scale, it showed a weak negative correlation with precipitation and a positive correlation with temperature. ④ During the 21-year period, there was a significant decrease in the area of agricultural land, a large increase in the area of forestland, a slight decrease in the area of grassland, and little change in the areas of urban and built-up land and water. One of the reasons for the increase in the NDVI throughout the 21-year period in the Hengduan Mountains region is the large increase in forested land area. [Conclusion] There were significant temporal and spatial variations in vegetation cover in the Hengduan Mountains. Temperature and precipitation influenced both vegetation cover and land use as driving factors of vegetation cover change.