Abstract: The paper makes a scientific evaluation and influencing factors on the air quality of Chengdu from 2010-2014.Based on the monitoring data of three kinds of air pollutants(PM10,SO2,NO2),the fuzzy comprehensive evaluation method was used to evaluate and grade the air quality of Chengdu from 2010 to 2014.Then the paper applied the grey correlation analysis method to calculate the correlation degree between the three kinds of air pollutants and nine influencing factors of air quality,and quantitative identification of the main factors affecting the air quality.The results showed that the air quality of Chengdu has been worsening.The main influencing factors of air quality are the urban population,the proportion of secondary industry and industrial dust discharged,which have high correlation of 0.8 with three kinds of air pollutants.