CeO(OH)(2) and Ce(OH)(4) capped on cerium oxide were observed in x-ray photoemission spectroscopy. Since the cerium oxide surface is partially covered with hydroxide before Si deposition, the Si layer is expected to have a poor crystal quality at the initial Si growing stage. Cross-sectional transmission electron microscopy analysis verified that there was not SiO2, but amorphous Si and Ce2O3 between the Si overlayer and CeO2. The reason why SiO2 is not formed is explained. The transition of the growth mode for the Si overlayer was observed in atomic force microscopy images. It is confirmed that the growth mode of Si on CeO2/Si is step Row at the low deposition rate and island growth at the high deposition rate.