Time series spectral remote sensing vegetation index is considered an effective index for monitoring vegetation coverage change and plays an important role in monitoring the dynamic change of vegetation coverage in a large area. Qilian Mountains, located at the junction of Gansu and Qinghai provinces, play an important role in maintaining ecological security in western China. In recent years, affected by global climate change, the climate in Qilian Mountains has changed to different degrees, and the state has implemented a series of environmental protection projects in the Qilian Mountains. Given the lack of research on the status and future trends of vegetation coverage in different ecological regions of Qilian Mountains, this research based on SPOT-VGT-NDVI spectral data with a resolution of 1km, used mathematical statistics and spatial superposition method to analyze the spatial and temporal patterns, vegetation stability and future evolution trend of vegetation coverage in different ecological regions of Qilian Mountains, and explored sensitive areas. It provides a theoretical basis for regional ecological security and ecological engineering construction, and further provides a scientific basis for forest and grassland departments to formulate Qilian Mountain protection planning and vegetation restoration measures. The results show that: From 1998 to 2018, vegetation NDVI in Qilian Mountains showed a fluctuating upward trend, with an increased rate of 0.32%·a^-1. The NDVI variation rates in the desert ecological area of Qaidam Basin and the Alpine desert steppe ecological area of the Palmier-Kunlun Mountain and the Altun Mountains were relatively low, only 0.14%·a^-1 and 0.27%·a^-1, while the variation rates in the steppe desert ecological area of the central Inner Mongolia Plateau and the river source area of the Gannan alpine meadow steppe were relatively large, respectively 0.54%·a^-1 and 0.57%·a^-1. Spatially, the vegetation NDVI of the Qilian Mountains is high in the southeast and low in the northwest, with overall improvement and partial degradation. The areas of degraded and improved areas accounted for 28.37% and 40.76% of the total area of the Qilian Mountains, respectively. The vegetation in the Qilian Mountains is relatively stable. The areas with relatively high fluctuations and high fluctuations total 0.22×10⁴ km², accounting for 1.20%. In the future, areas with a benign development trend and a malignant development trend account for 42.82% and 26.40% of the total area of the Qilian Mountains, of which the area with continuous degradation accounts for 25.56%. The degraded areas mainly include the alpine steppe and alpine desert near the high altitude snow line and the fragile vegetation areas around the towns, rivers and lakes. The country should take this area as the key area of vegetation restoration.