The accurate identification of aerosol types is an important prerequisite for further research on its climatic and environmental effects. In this study, based on the observation data of ground-based dual-wavelength polarization lidar from the Semi-arid Climate and Environment Observation Station of Lanzhou University from October 2009 to November 2012, several cases were selected under four typical scenarios: clean day, anthropogenic pollutants, dust events and strong sandstorm events. The aerosol extinction coefficient, volume linear depolarization ratio and aerosol depolarization ratio were analyzed statistically, and the determination thresholds of different aerosol types were defined. The results show that the extinction coefficient of aerosol in this region is less than 0.085 km^-1 on clean day. When the extinction coefficient is greater than 0.085 km^-1, the volume linear depolarization ratio of anthropogenic pollutants is less than 0.07, and the corresponding aerosol depolarization ratio is less than 0.09. The volume linear depolarization ratio of polluted dust is between 0.07 and 0.22, and the aerosol depolarization ratio is between 0.09 and 0.31. The volume linear depolarization ratio of pure dust is greater than 0.22, and the aerosol depolarization ratio is greater than 0.31. In particular, when severe sandstorms occur, the volume linear depolarization ratio is greater than 0.35, and the aerosol depolarization ratio is greater than 0.49.

In order to study basic aerosol optical properties in arid agricultural region during the farming season，a field campaign was carried out using the ground aerosol integrated observation system at the Huangyangzhen Farm site in Wuwei of Gansu Province in April of 2014． Results show that the scattering coefficients of PM2． 5 and PM1． 0 at the Huangyangzhen Farm site in Hexi Corridor were 98． 2 ± 38． 3 Mm ^{－ 1}，74． 6 ± 29． 1 Mm ^{－ 1}，respectively． The absorption coefficient of PM2． 5 was 8． 8 ± 6． 3 Mm ^{－ 1}． These values were all smaller than that observed in the central － eastern regions of China． The SSA was 0． 90 ± 0． 03，and the Angstrom exponents of PM2． 5 and PM1． 0 were 1． 31 ± 0． 29 and 2． 10 ± 0． 24，respectively． Diurnal variation of aerosol scattering and absorption coefficients appeared two peaks，while SSA appeared two valleys values． Aerosol was greatly influenced by anthropogenic aerosol at Huangyangzhen site． Scattering and absorption coefficients of aerosol from the western，the southwestern and the southeastern regions were larger，and aerosol from the northeastern direction contained more dust aerosol generated by agricultural activities．