Based on the continuous observation data of lidarthe aerosol backscattering coefficient (355/532/1064 nm)extinction coefficient (532/607 nm)depolarization ratio (532p/532s)lidar ratio (532nm) and backscatter-related A°ngstrm exponent (355/532nm and 532/1064nm) are retieved. Thenthe aerosol optical properties of three different pollution episodes (air pollution/polluted dust/pure dust) in Beijing in October 2019 are analyzed. Results show that the air pollution aerosol depolarization ratio at 532nm (A°ngstrm exponent between 355 and 532nm) is 0.10±0.02(1.2±0.19)and the lidar ratio at 532nm (43±7sr) is lower than that of typical urban pollution aerosolwhich is probably affected by hygroscopic growth of water-soluble aerosolssuch as nitrate or the formation of secondary organic aerosols. In the polluted dust episodethe depolarization ratio (A°ngstrm exponent) is 0.19±0.03 (1.0±0.35)and the lidar ratio is 51±7sr. In the pure dust episodecompared with the formerthe depolarization ratio (0.25±0.03) is largerthe A°ngstrm exponent (0.11±0.44) is smallerand the lidar ratio is 40±4sr.