The structure and growth process of Au particles on CeO2 were observed by the transmission electron microscope (TEM) equipped with the high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) system. The growth of Au particles on CeO2 was shown to be mainly Ostwald ripening under heating at various temperatures, although it is suppressed in the hydrogen atmosphere. In the HAADF-STEM observation of Au/CeO2 interfaces with the orientation relationship of (111)[1-10]Au//(111)[1-10]CeO2, (111)[-110]Au//(111)[1-10]CeO2 and atomic columns of Au and Ce were successfully resolved, and the interface structure was analyzed in details for the first time.