The work aims to improve the water and gas barrier properties of polyvinyl alcohol (PVA) in a safe and environmentally friendly manner, prepare a high barrier PVA coating and improve the performance and application range of PVA. Polyvinyl alcohol and cellulose nanofiber were blended. On this basis, stearic acid was added to conduct water resistance modification to explore its effect on the barrier performance. The structure and properties were characterized by Fourier infrared spectroscopy, XRD, oxygen and water vapor transmission tester. The results showed that the esterification reaction of stearic acid and PVA could improve the water resistance of the coating, and the hydrogen bond could be produced between PVA and CNF to improve the crystallinity and barrier property of the coating. The addition of appropriate stearic acid did not reduce the crystallinity of CNF, but only reduced the crystallinity of PVA. When the amount of stearic acid was 16%, the water vapor transmission of the coating reached the lowest 2.2 g/(m2.d) and the oxygen permeability reached 1.3 cm3/(m2.d). PVA barrier coating prepared by CNF blending and stearic acid esterifying has high barrier property, which makes it have broad application prospects in barrier coatings.