Disclosed is a method of bonding a battery case frame and a cooling plate in a process of producing an electric vehicle battery case, including a cooling plate preparation operation of preparing the electric vehicle battery case and the cooling plate and forming injection part fixing holes in the battery case and the cooling plate, a mold seating operation of temporarily assembling the electric vehicle battery case and the cooling plate, seating the temporarily assembled electric vehicle battery case and cooling plate in an injection mold, and forming an injection molding space communicating with the injection part fixing holes and having a predetermined volume, an injection operation of filling the injection molding space of the injection mold and the injection part fixing holes with a preset injection material, and a bonding completion operation of separating the electric vehicle battery case from the injection mold.