Taking 12 league cities in the ecologically fragile region of Inner Mongolia as the research object, the comprehensive evaluation index system of economic-social-ecological environment system was constructed. The weight was calculated based on entropy method, and the comprehensive score of 12 league cities from 2010 to 2019 was calculated by linear weighting method, and then the ranking and comparison were made. The results show that : The overall status of Inner Mongolia was in the order of attaching importance to economy > ecological environment > social system. There was a big gap in economic development and a small difference in social and ecological environment system. Factors leading to the score of comprehensive development level were different. In 2019, Ordos City, Hulunbuir City, Baotou City and Hohhot City had better comprehensive development. General development mainly concentrated in Chifeng, Xilin Gol League, Xingan League, Tongliao City. Poor development concentrated in Bayannur City, Alxa League, Wulanchab City, Wuhai City.