Abstract: In this paper, a synergy of the moderate resolution imaging Spectroradiometer (MODIS) onboard Terra and Aqua satellites (SYNTAM) algorithm was improved to retrieve the atmospheric aerosol optical thickness (AOT) in Beijing region, and its results were compared with the Aerosol Robotic Network (AERONET) observations as ground truth in order to be validated. Firstly, a series of statistical values were obtained based on the corresponding AOT values from retrieval, in accordance with a convolution scheme with a pre-defined fixed window size. Secondly, the results of the AERONET observations associated with both spatially and temporally were contrastively analyzed to find the relevant correlations between the fore and the latter, and the effectiveness of the SYNTAM algorithm was properly assessed. The results show that the improved algorithm is greatly applicable and available in Beijing region because the AOT values, retrieved by it, are very highly consistent with the real values on related ground sites, and is quite significant with respect to air environmental monitoring and effect analysis of sun-light stress for crop growing.