With the rapid development of the global economy, the ecological environment is deteriorating, and it is urgent to carry out environmental change monitoring. The rise of remote sensing technology has made it possible. As an important ecological barrier in northern China, Hulunbuir City has been receiving much attention. Currently, the ecological environment monitoring of Hulunbuir focuses on the use of multi-period remote sensing images, combining with climate data, and a single driving force analysis method to study the changes in local vegetation and to explore the response of vegetation changes to the natural climate. However, there are few studies on the impacts of human activities on vegetation changes. Most of them are based on qualitative analysis or human activities as a whole, which is difficult to determine the specific driving force components and the influence direction and the extent of each component factor. This paper is based on SPOT/VEGETATION NDVI data from 1998-2018, combined with the terrain, climate and Human activity data, and comprehensively applying the trend analysis, coefficient of variation method, pixel decomposition model, principal component analysis, multiple linear regression, ridge regression and so on to carry out the qualitative and quantitative analysis of the spatio-temporal changes and driving forces of Hulunbuir's fraction of vegetation cover (FVC). The results show:(1) during the 21 year, the FVC in the study area slowly increases in low fluctuations, with a period of 4-5 years, during which the FVC first decreases and then increases, and there is a change pattern of "decreasing in the west and increasing in the east" in space. The FVC types are mainly extremely high and high, and the areas of medium, low, and extremely low are decreasing, and the sum only accounts for 10%-15% of the study area. The increase of extremely low and low type area is relatively large, which are 36.80% and 98.46%, respectively. The main source is the degradation of medium and high type, and the increase of extremely high type area is relatively large, which is 33786.03 km², and the main source is the further improvement of high type. (2) The areas with significant and extremely significant increases account for 53.56% (135720.57 km²), the areas with insignificant changes account for 42.28% (107140.74 km²), and the areas with significant and extremely significant decreases only account for 4.17% (10569.06 km²) of the research area. (3) There are obvious differences in the driving force of the FVC in different regions. Topographical factors lay the spatial distribution pattern of "low west and high east" and climatic factors affect the temporal distribution pattern of FVC. New Barag Right Banner, New Barag Left Banner, Ewenki Autonomous Banner, Arun Banner and Chen Barag Banner are dominated by climatic factors. Yakeshi, Erguna, Genhe City and Zhalantun is dominated by human activities factors, while Manzhouli, Hailar and Oroqen Autonomous Banner are affected by climatic factors and human activities factors. The influence of driving factors on Hulunbuir's FVC changes is bidirectional. With the correct policies and reasonable planning, it is possible to achieve a win-win situation for socio-economic development and sustainable development of the ecological environment. The research results provide the theory and data support for Hulunbuir's sustainable development of ecological environment and grassland protection policy.