Aerosol optical properties were continuously measured with the National Institute for Environmental Studies (NIES) compact Raman lidar over Beijing, China, from 15 to 31 December 2007. The results indicated that in a moderate pollution episode, the averaged aerosol extinction below $1\mathrm{km}$ height was $0.39\pm 0.15{\mathrm{km}}^{-1}$ and the lidar ratio was $60.8\pm 13.5\mathrm{sr}$ ; in heavy pollution episode, they were $1.97\pm 0.91{\mathrm{km}}^{-1}$ and $43.7\pm 8.3\mathrm{sr}$ ; in an Asian dust episode, they were $0.33\pm 0.11{\mathrm{km}}^{-1}$ and $38.3\pm 9.8\mathrm{sr}$ . The total depolarization ratio was mostly below 10% in the pollution episode, whereas it was larger than 20% in the Asian dust episode. The distinct characteristics of aerosol optical properties in moderate and heavy pollution episodes were attributed to the difference in air mass trajectory and the ambient atmospheric conditions such as relative humidity.