Atmospheric aerosol mass concentration was investigated in Gulou,Jiangbei,Zhongshan districts and Ningliu highway traffic of Nanjing in spring,summer,and autumn by Anderson-Ⅱ-type 9 crash sampler. Results show that the concentrations of PM_2.1 and PM₁₀ revealed obviously seasonal variations: autumn>spring>summer. The concentrations of PM₁₀ are 167.47 μg/m³ in spring,85.99 μg/m³ in summer,and 238.99 μg/m³ in autumn. The concentrations of PM_2.1 are 59.66 μg/m³ in spring,42.80 μg/m³ in summer,and 100.15 μg/m³ in autumn. The correlation between PM_2.1and PM₁₀ appeared well in different seasons with the best correlation coefficient of 0.952 in summer,0.783 in autumn,and 0.613 in spring. The concentrations of PM_2.1 and PM₁₀ differed greatly in various functional areas: traffic source>industry district>business district>scenic spot. The mass concentration spectral in different areas distributed bimodally with the peak values at 0.43-0.65 and 9.0-10.0 μm/m³. The particles' mass concentration spectral showed bimodal distribution in spring,summer,and autumn of Nanjing,which were mainly focused at the diameter of 0.43-3.3 μm/m³. The correlation coefficient between PM_2.1 and PM₁₀ was 0.184 in Jiangbei district,which was slightly higher than that in Gulou district (0.797).