CERES/TRMM Single Satellite Footprint (SSF) with merged cloud, aerosol, and radiation data in 1998 is becoming available to the science community. The quality of the data products will become the major research focus before the data is widely used for radiation and climate studies. In our paper, we will validate the aerosol products of the 1998 CERES/TRMM SSF data with ground based Sun/sky radiometer observation of the Aerosol Robotic NETwork (AERONET). We select quality controlled (Level 2) sun-photometer aerosol data (optical thickness and size parameter) at thirteen AERONET marine stations and co-locate them with SSF aerosol retrievals in a match-up time/space window. The statistics are calculated for the match-up data to assess the systematic and random errors of the aerosol retrievals in the SSF data. The validation results will also be compared with the 1998 aerosol retrievals from NOAA-14/AVHRR since the retrieval algorithms on the two space platforms are basically the same. Assumptions in calibration, surface reflectance, and aerosol model in the aerosol retrieval algorithm will be evaluated for future improvement.