The effect of textures produced by various types of deformation processing on gas barrier property of copolymer film has been studied in the case of ethylene-vinylalcohol (EVOH) resin which is known as a semicrystalline polymer with low gas permeability.The heavily cold rolling and cold stretching give rise to highly oriented molecular structures and strong crystallographic textures, which reduce gas permeability of the film at high humidity. It was found, in particular, that the increased tri-axial orientation type texture and resulting molecular structure changes due to the plane strain compression type deformation, such as rolling, improved greatly the barrier property of the EVOH film.