Abstract: Based on the GIMMS NDVI 3g.v1 data from 1982 to 2015, the trend of vegetation cover change and its influencing factors on the southern slope of Qilian Mountain were analyzed by trend line method and correlation analysis method. The results showed that: (1) The vegetation coverage on the southern slope of Qilian Mountain showed a significant upward trend, and the linear regression growth rate was 0.99%/10a. The average NDVI in each season was summer>autumn>spring>winter, and the order of NDVI change rate was winter>summer. >Autumn>Spring; the monthly NDVI trends in each stage were basically the same, and the summer vegetation coverage was the largest in 2004-2015. (2) In the past 30 years, most of the southern slope of Qilian Mountain belongs to the evergreen area. The area of vegetation increase in the three-time period showed an increase-decrease-increased trend, and the area of vegetation increased between 2004 and 2015 was the largest. 92.66%, the fastest growing area in Menyuan County. (3) From 1982 to 2015, the correlation between NDVI and temperature in the study area (0.58) was greater than that of rainfall (0.27). The vegetation cover in the growing season (April-September) of the study area was affected by both temperature and precipitation.