Using TM/ETM images of Inner Mongolia Autonomous Region in 1990, 1995, 2000, 2005, 2010, 2015 and 2018 as data sources, land use data of Inner Mongolia Autonomous Region based on GIS was extracted. Using the calculation method of China Terrestrial Ecological Service Value Table, the land use data of Inner Mongolia Autonomous Region was analyzed and the ecological service value was calculated. The results showed that: From 1990 to 2018, the land use and land types in the Inner Mongolia Autonomous Region as a whole showed a changing trend in space and time. The specific changes were as follows: The cultivated land, forest land, and unused land are on the decline, the grassland and urban construction land are on the rise. The unused land had the largest reduction in area, and the grassland had the largest increase in area. Combined with the land-use transfer matrix, the reduced unused land, forest land, and cultivated land were mainly converted into grassland. In the past 30 years, the value of ecological service in Inner Mongolia had shown an overall growth trend, with the highest value of grassland ecological service and the lowest value of unused land ecological service. Sensitivity index of ecological service value was < 1, and it indicated that the value of ecological services in Inner Mongolia has been relatively stable in the past 30 years and the results were credible.