Abstract: Using Landsat NDVI sequence data from 2000 to 2020 as the data source, this paper used spatiotemporal and statistical analysis methods to explore the spatiotemporal variation characteristics of grassland vegetation coverage and grassland degradation in northern Xinjiang. The driving forces of grassland degradation in Northern Xinjiang were analyzed from two aspects： climate and human activities. The results showed that from the spatiotemporal changes of grassland vegetation coverage, the overall trend of grassland vegetation coverage in Northern Xinjiang from 2000 to 2020 was increasing;the ecosystem in the Northern part of Xinjiang was more fragile and susceptible to the impacts of climate change and human activities;the grassland in the Northern Xinjiang region had a relatively high grassland vegetation coverage on the sunny slope. The areas with a high grassland vegetation coverage were mainly located in mountainous areas with high terrain index and relatively good water and thermal conditions. The areas with a low grassland vegetation coverage were mainly located in areas such as relatively water scarce and arid desert edges. From the spatiotemporal variation characteristics of grassland degradation, there was a significant shift in the levels of grassland degradation in Northern Xinjiang from 2000 to 2020, mainly manifested as the transition from mild and moderate degradation to non degraded grassland, and from severe degradation to mild degradation, indicating that the phenomenon of grassland degradation in Northern Xinjiang had further improved. Grassland degradation in Northern Xinjiang was the result of the combined effects of climate change and human activities, with precipitation being the main climate factor.

Key words: Landsat NDVI, grassland vegetation coverage, grassland degradation, spatiotemporal variation, Northern Xinjiang