Using the data of Aerosol Robotic Network (AERONET) in Beijing site from January 2016 to December 2018, the seasonal characteristics of aerosol optical depth (AOD), Angstrm exponent α, sizedistribution in Beijing were analyzed. Meanwhile, the characteristics of contaminant and lidar ratio were analyzed under typical pollution conditions. The results show that the seasonal variation of AOD in Beijing is obvious, its value is higher in spring and summer than autumn and winter. Especially in summer, the value (0.83) is significantly higher. The variation of Angstrm exponent α shows the similar regularity with AOD, with the lowest in spring (α=0.95) and the largest in summer(α=1.23), indicating that the main pollutant is dust in spring and fine particle in summer regarding to the typical temperate monsoonal climate. The diagram of AOD and α shows that the distribution of different pollutants have different characteristics, thresholding method can be used to classify the pollutant. Moreover, lidar data in two typical pollution cases was analyzed and the extinction coefficients were obtained by using different lidar ratios, and it shows that the solar photometerdata can be used to optimize the inversion parameters.