The invention relates to the field of tyre mold structures, and discloses a sealing device and a vacuum tyre mold. The sealing device is matched with a side plate and a base and/or an upper cover of the tyre mold so as to seal the tyre mold. The sealing device further comprises a sealing piece, wherein the sealing piece is arranged on the inner side of a radial direction of the base and/or the upper cover, is located on a matching surface of the base and/or the upper cover and the side plate, and extends from the inner side of the radial direction of the base and/or the upper cover to the outer side of the radial direction of the base and/or the upper cover. The vacuum tyre mold is simple in structure, outstanding in sealing effect and convenient to maintain.