From November 1, 2017 to May 15, 2018, the micro-pulse lidar level detection was carried out at the Quancheng Square substation in Jinan. During the experiment, the visibility meter, conventional pollutant monitoring and PM2.5 chemical composition monitoring were simultaneously observed. In this experiment, the visibility meter was defined as the reference layer. And the horizontal aerosol extinction coefficient was calculated by using the Fernald method. The relationship among PM2.5 concentration, extinction coefficient and PM2.5 chemical components was established by linear regression model. The inversion accuracy of the relationship was studied by trend comparison, correlation coefficient and standardized mean deviation. The results show that the extinction coefficient is more accurate by combining with visibility meter; the inverse extinction coefficient has a good positive correlation with PM2.5 mass concentration (correlation coefficient R=0.75), and the extinction coefficient and PM2.5 mass concentration are all related to O■,NH■■ , OC, NO■■, EC in PM2.5 chemical components. The relationship among PM2.5 concentration, extinction coefficient and chemical components of PM2.5 is established by linear regression model. The mass concentration of PM2.5 retrieved from the quantitative relationship is basically consistent with the actual monitoring value, and the correlation number is 0.83. The average standard deviation is 18%, and the relative deviation is small.