A method for integrally molding a metal and a resin and a metal-resin composite structure obtainable by the same are provided. The method comprises forming a nanopore in a surface of a metal sheet; melting a thermoplastic resin on the surface of the metal sheet formed with the nanopore; and injection molding the thermoplastic resin onto the surface of the metal sheet. The thermoplastic resin is a mixture of a main resin and a polyolefin resin, the main resin is a mixture of polyphenylene oxide and a polyamide, and the polyolefin resin has a melting point of about 65° C. to about 105° C.