Abstract: Provided is a compression molding die. The die can be used for compression molding an I-shaped part without the need for machining. The molding die comprises: an outer mold with an inner diameter of d; an upper pressing disc, a lower pressing disc and a huff mold with the same outer diameter of d and the same inner diameter of f; an upper mold; a lower mold; and a core mold with a diameter of h. The upper pressing disc, the huff mold and the lower pressing disc, which are movable vertically, are arranged in the outer mold in a vertically spaced manner; the vertically movable upper mold extends into the upper pressing disc, and the vertically movable lower mold extends into the lower pressing disc; the outer mold, the upper mold, the upper pressing disc, the huff mold, the lower pressing disc and the lower mold define a cavity.