The invention relates to a lithium ion battery flexible package film. The package film comprises a thermal resistant protective layer, a first adhesive layer, an aluminum foil layer, a passivation layer, a second adhesive layer and a thermal-plastic resin film layer from the external to internal in sequence; a physical blocked layer is arranged between the passivation layer and the second adhesive layer; the physical blocked layer is formed by drying and curing coating liquid on the surface of the aluminum foil passivation layer, wherein the coating liquid contains graphene microstrip and siloxane; the PH value of the coating liquid is 3-5; the coating liquid comprises 0.5-2wt% of micromolecular organic acid, 2-10wt% of organic siloxane, 0.01-0.1wt% of micromolecular alcohol, 0.1-1wt% of graphene microstrip, 0.05-0.2wt% of dispersant and the balance of deionized water in percentage by mass. Vapor and oxygen molecules on the exterior of a battery are difficult to permeate into the battery through the physical blocked layer so as to prevent the cell material from being deteriorated; HF acid in the electrolyte also can be prevented from permeating to the aluminum foil layer so as to prevent the separation of the aluminum foil and an inner film caused by corrosion of the aluminum foil by the HF acid; and therefore, the lithium ion battery flexible package film has the advantage of long service life.