A process for forming a dense, epitaxial metal oxide film on a single crystal substrate, including cleaning the surface of the single crystal substrate, contacting the cleaned surface with a polar organic compound such as a small molecular weight alcohol, so that the cleaned surface adsorbs the polar organic compound, then applying a hydrocarbon solvent solution containing at least one organic group-containing metal compound on the polar organic compound-adsorbed surface, and then heating the substrate to decompose the organic group-containing metal compound and to form a dense epitaxial metal oxide film on the substrate.