The annual and seasonal variation characteristics of AQI and primary pollutants in LinfenCity were analyzed based on the daily air quality data from 2017 to 2020. The air quality was evaluatedusing comprehensive pollution index method. The results show that,from 2017 to 2020,the number ofdays with good air quality is increasing year by year,while the number of days with light pollution andabove is decreasing year by year. The emission of pollutants is affected by the total consumption of coalenergy,private car ownership,green coverage,the proportion of the secondary industry and industrialdust emissions. The air quality is good in summer,bad in winter and general in spring and autumn.PM2.5 is the main pollutant in autumn and winter,and O3 is the main pollutant in summer. The yearsranked from good air quality composite index to bad are 2020,2019,2018 and 2017. The air qualitylevel of Linfen city is moderate pollution in 2017 and 2018,and is slight pollution in 2019 and 2020.The air quality has improved,but it still needs further control and treatment.