The invention provides a high-barrier layer flexible packaging film for isolating contents of a polymer lithium battery. The high-barrier layer flexible packaging film comprises at least two kinds of films which are combined to form a layer of composite film, wherein the composite film comprises a basic layer, a functional layer and a heat sealing layer; the high-barrier layer flexible packaging film is characterized in that: the basic layer is a copolymer film prepared by combining at least two film base materials of PP (polypropylene), CPP (chlorinated polypropylene or casting polypropylene), PE (polyethylene), PET (poly(ethylene terephthalate)), PA (polyamide) or MXD6 (aromatic polyimide), MPE (elastomer blend), PVDC (polyvinyl dichloride), EVOH (ethylene-vinyl alcohol), PEN (polyethylene naphthalate) and GT, or by complexing pairwise; and a high-barrier water-tolerant modified PVA (poly vinyl alcohol) coating film is coated on the copolymer film base materials. The high-barrier layer flexible packaging film has excellent gas barrier property, remarkably low oxygen permeability, water resistance, corrosion resistance, good high temperature resistance and great barrier property, and resists organic solvents and highly-volatile substances. In the invention, the high-barrier PVA is preferably coated on various base materials to obtain a base layer serving as a high-barrier layer which has great barrier property and excellent performance in resisting gas, water, corrosion, ultraviolet rays and the like.