First, the factor analysis method is used to calculate the index values of the 6 monitoring sub‐indexes in the AQI, including PM2.5, SO_2, NO_2, PM10, CO, and O_3, and the correlation coefficients between the pollutant contents, and the 5 indicators are quantitatively analyzed. The strength of the correlation between PM2.5 and SO_2, NO_2, PM10, CO has a strong positive correlation, and a weak negative correlation with O_3. On this basis, a multiple linear regression model of PM2.5 (content) and other five sub‐indices and their corresponding pollutants (content) was established.