The modeling system RAMS-CMAQ is applied in this paper to East Asia to simulate the temporo-spatial concentration distributions of atmospheric aerosols. For evaluating its performances, modeled concentrations of aerosols such as sulfate, nitrate, ammonium, black carbon and organic carbon were compared with observations obtained in East Asia on board of two aircrafts in the springtime of 2001. The comparison showed generally good agreement, and, in particular, that the modeling system captured most of the important observed features, including vertical gradients of the aerosols of the Asian outflow over the western Pacific. The evaluation results provide us with much confidence for further use of the modeling system to investigate the transport and transformation processes of atmospheric aerosols over East Asia and to assess their impacts on the Earths radiation budget.