The phase equilibrium of the LiVO3‐LiNbO3pseudobinary system has been investigated, and a LiNbO3single‐crystal thin film has been grown epitaxially onto the substrate by dipping ac‐plate LiTaO3substrate into a LiVO3flux solution. An x‐ray rocking curve indicated that the film had a high single crystallinity with good epitaxy. The composition ratio Li/Nb of the film was estimated to be close to the stoichiometric value Li/Nb≈1.0.