With the increasing proportion of open-pit coal mining in the coal mining industry in China, a series of potential safety hazards, environmental pollution, ecological damage and other problems caused by open-pit coal mining have attracted a great deal of attention. Scientifically determining the appropriate mining right scope of an open-pit coal mine can prevent various problems caused by coal mining from the source. In this study, according to the characteristics of open-pit coal mining and the environmental characteristics in arid areas, 15 indicators were selected and their weights were determined from the three perspectives of geological environment, social environment and ecological environment by using the AHP. Based on the spatial analysis function of ArcGIS, a digital evaluation model was established for the corresponding influencing factors, and a comprehensive evaluation model for setting the mining right range was constructed by superimposing the weights. Finally, four mining areas were identified within the study area in Wuhai, Inner Mongolia, and their ecological values were calculated to determine the mining area with the lowest ecological impact.