Abstract: The aerosol scattering coefficient (σsp) data observed at Shangdianzi atmospheric background station from 2004 to 2006 have been used to analyze the characteristics of aerosol in the background region. The results show that the mean annual σsp was relatively low with a slight increase in 2006, which is specially caused by frequent dust pollutions happening during the spring. Diurnal change has a dropping trend in the daytime and a rising trend at night, which accords with the daily change of atmospheric stratification. Seasonally, the values of σsp in winter and spring were lower than that in summer and autumn. Moreover, weather impacts aerosol obviously. The mean σsp in sunny days was much lower than that in cloudy condition, due to the strong convection that can increase the aerosol diffusion in sunny days. The air from eastnortheast east was clean, which could decrease σsp, while southwest wind could bring more polluted air and cause the increase in σsp, which shows that the city activities had an effect on the atmosphere at the observing site. Finally, the background value was calculated through the most frequent statistics value, which was in the range of 10-20 Mm-1.