A detachable threaded rod is used in an injection mold, and includes an operation portion, a molding portion, and a screw. The operation portion includes a rod part, the rod part defines a mating hole and a screw hole on a bottom surface of the mating hole. The molding portion includes a front end, a rear end, and a side surface connected between the front end and the rear end. The molding portion defines a cavity on a front end. The molding portion includes a mating portion extending from the rear end and received in the mating hole. The mating portion defines a through hole communicating with the cavity. The molding portion defines external threads on the side surface. The screw penetrates the through hole and screwing in the screw hole, the operation portion is fixed with the molding portion by the screw.