We analyzed vegetation change tendency in Hulunbuir and Xilingol in the Inner Mongolia Plateau of China by using the normalized difference vegetation index (NDVI) time series from the Global Inventory Modeling and Mapping Studies Advanced Very High Resolution Radiometer data set between 1981 and 2010. We used ordinary least squares to analyze changes in grassland greenness in Hulunbuir and Xilingol over 30 years. In the study area, we selected 24 coal-mining areas; detected the changing trend of greenness in the mining areas and their surrounding 10 km, 20 km and 50 km buffer zones; and analyzed the correlation of NDVI between the mining area and its corresponding buffer zones. We obtained the following results:(1) from 1981 to 2010, 59.16% of the regional NDVI in the growing season (GNDVI) showed a decreasing trend in Hulunbuir, and 73.13% of the regional NDVI showed a decreasing trend in Xilingol, which indicated that greenness generally decreased in both Hulunbuir and Xilingol. (2) In the map of Hulunbuir, pixels indicating grassland vegetation greenness reduction were located widely, and those indicating greenness increase were located in the northeast; in the map of Xilingol, pixels indicating grassland vegetation greenness reduction were located in the east and southwest, and those indicating greenness increase were located in the northwest. (3) Both coal mining areas in Hulunbuir and Xilingol showed a decreasing greenness trend, and this trend in Xilingol trend was more obvious. (4) Both opencast mining and underground mining for coal have negative impacts on greenness. (5) GNDVI can reflect land reclamation in mining areas.