Abstract: Six conventional air pollutants in Chongchuan District of Nantong City in 2018 were analyzed. The time distribution characteristics and internal relations of pollutants were studied to conduct the comprehensive evaluation of air quality. Based on the results of factor analysis,PM₁₀,PM_{2. 5},SO₂,NO₂,and CO were positively correlated,while only O₃ wassignificantly correlated with CO at the level of 0. 05. The extracted eigenvalues were 4. 149 and1. 041,respectively. The cumulative variance contribution rate was 86. 505% of the information. Factor 1 could be interpreted as the impact factor of primary pollutants. Factor 2 could be interpreted as the impact factor of secondary pollutants. The pollution of the first pollutant was the least in August and the most serious in January,The secondary pollution was the least in December and the most serious in April. On the basis of the comprehensive score ranking,it could be seen that the air quality from June to October in the whole year was better than other months. However,the worst was found in January and April.