Abstract: In order to compare the air quality of Beijing and Hohhot and discuss the different causes and the prevention and control measures of air pollution, the characteristics of air pollutant quality concentration, primary pollutant change and air quality index of the two cities was analyzed based on the regular monitoring data of air quality of the two cities from January 2014 to December 2019 released by Environmental Monitoring Station of China. The results showed that: The pollutants in the atmosphere of Beijing and Hohhot, including PM₁₀, PM_2.5, SO₂, NO₂ and CO, shared similar seasonal variation characteristics. The air quality of both cities was the best in summer and the worst in winter. The chief pollutant contributing to the air quality of the two cities was particulate matter, with PM_2.5 in Beijing and PM₁₀ in Hohhot. Long-term monitoring data showed that the concentration of pollutants in the air of the both cities present a continuous downward trend with the rapid development of economy and society, while the concentration of O₃ was still increasing. According to the correlation analysis between the economic index and pollutant concentration in the two cities, high-quality urban development is increasingly constrained by air quality, improving urban economic structure plays an important role in preventing and controlling air pollution.