Abstract: The present application discloses a high-barrier polyolefin composite film, including, from the outside to the inside, an outer PE film, a water-barrier layer, a high-barrier PVA coating layer, an adhesive layer, and an inner PE film, wherein the inner PE film comprises the following raw materials in percentage by weight: 10-20% of HDPE, 30-50% of MDPE, 20-26% of LLDPE, 10-20% of LDPE, 8-12% of a water- and oxygen-barrier masterbatch, and 1-3% of an auxiliary agent; the water- and oxygen-barrier masterbatch includes the following raw materials in parts by weight: 10-20 parts of polycarbonate, 0.1-0.3 parts of a compatibilizer, 10-20 parts of an ethylene-vinyl acetate copolymer (EVA), 1-2 parts of single-layer graphene, and 1-2 parts of polyhedral oligomeric silsesquioxane.