Abstract:This study analyzed the spatio-temporal variation of atmospheric Aerosol Optical Depth (AOD) in Beijing and surrounding areas from 2000 to 2013 by utilizing the AOD data from the Moderate-resolution Imaging Spectroradiometer (MODIS) aboard NASA Terra satellite and the in-situ observations of meteorological parameters from 142 weather stations in Hebei Province, and discussed the key meteorological factors that affect the spatio-temporal variation of atmospheric aerosol through studying the relationship between AOD and various meteorological parameters. The results show that the AOD in the southern area of Beijing reaches the maximum in summer, followed by spring, while the AOD in autumn and winter is relatively low. The AOD in the northwest of Hebei is lower than that in the southeast. The interannual variation of AOD in the dam area is significantly lower than that of other regions, while the interannual variation of AOD in the plain area is similar to that in the coastal area, with higher AOD in spring and summer than autumn and winter. In spring, the relative humidity plays an important role in affecting AOD, and the peak values of AOD range from May to July, accompanied with higher relative humidity, lower visibility, southerly wind, lower surface wind speed and stable atmospheric stratification., the degree of contamination of stations in Hebei province to the south of Beijing is similar to that in Beijing, and the AOD observed in the southern stations is higher than that in the northeastern stations. This may be due to the fact that the anthropogenic aerosol emissions are mainly concentrated in the industrialized cities to the south of Beijing, and the diffusion direction of pollutant controlled by the southerly wind.