The substrate off-orientation effect is systematically studied on epitaxial CeO2(110) layers on Si(100), and the crystalline quality is significantly improved by enhancement of domains whose 〈110〉 is perpendicular to the offset-direction (Si〈110〉). AFM measurements indicate that the CeO2 layer surface consists of stripe-shaped facets and that their size is typically 100˜200 nm long, 20 nm wide and ∼3 nm high for a 150 nm-thick layer. RHEED and XTEM reveal that CeO2〈110〉 axis is inclined from wafer normal by the off-angle. The step arrangement at Si surface observed by XTEM relates closely to the inclination of the facets. It is found that off-orientation (≥∼,2.5°) leads to single crystal layer formation. RBS analyses verify that the crystalline quality is significantly improved, especially at the surface. The best result is obtained at the off-angle of 2.5°.