With the launches of the MODIS sensors on the Terra and Aqua spacecrafts, new data sets of the Earth surface are obtained, and a aerosol retrieval model by exploiting the synergy of Terra and Aqua MODIS data was promoted. Thereafter, its aerosol optical depth products have been continuously evaluated and validated. Most of these validation studies have shown that although MODIS generally derived aerosol optical depth to within the expected error, MODIS tended to poor quality when there is a visible difference in aerosol size distributions between the two pass observations time. To solve this problem, the model was improved, one visible channel was import, and the model was reconstructed. In order to validate what were mentioned above, a case study over Beijing was provided, and preliminary validations have been carried out by comparing with AERONET measured data. This algorithm has been tested. Compared with co-located AERONET site, the new MODIS algorithm retrieves aerosol optical depth more accurately than the previous. MODIS/AERONET tau regression has an equation of y = 1.0496x - 0.0106, R² = 0.9931.