Abstract: Based on the monitoring data of the ambient air quality in Guandu District from 2013 to 2019 and the data of the national acid rain monitoring site, the ambient air quality in this district in recent years was analyzed. Under the background of the substantial improvement of the air quality, the concentration of particulate matter was gradually controlled, while the problem of ozone pollution became increasingly prominent. The number of mildly polluted days decreased from 68 to 15, and the number of moderately polluted days decreased from 3 to 0. The number of days with particulate matter as the primary pollutant decreased from 80.3% in 2013 to 6.70% in 2019, while the number of days with ozone as the primary pollutant increased from 18.3% to 93.30%. According to the analysis of precipitation monitoring results and atmospheric environment monitoring results, precipitation in the whole region belongs to the mixed type of sulfuric acid and nitric acid, and the SO₄^2-/NO₃^- ratio decreased year by year, indicating that NO₃^- increased gradually and nitrogen oxide pollution intensified day by day. This paper put forward corresponding countermeasures for these problems in order to provide reference for the improvement of environmental air quality.