In recent years, with the increasing care of environmental issues, the relationship between air quality and the level of economic development has been widely studied. In the present paper, a traditional EKC model and two improved model are built to analyze the relationship between the air quality index and the per capita GDP with the panel data of 41 major cities during 2000 and 2015 of China. By the co-integration analysis, the results show that under the three-square EKC model, the

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... p between the AQI and GDP per capita satisfies the N-shaped environment Kuznets curve and there exist two turning points. In the form of the traditional two-square EKC model, the two variables are satisfied with the U-shaped relationship. The results of the growth rate model also show that the two variables are satisfied with the U-shaped relationship, but there are differences among the turning points.