The present invention relates to a cylindrical linear motor including: a primary structure, a secondary structure, a plurality of sets of fifteenth salient pole structures, a plurality of fifth permanent magnets, a plurality of sixth permanent magnets, and a plurality of windings. The primary structure and the secondary structure are both cylindrical, the primary structure is sleeved on the outerside of the secondary structure, the secondary structure is coaxially disposed with the primary structure, and the plurality of fifth permanent magnets and the plurality of sixth permanent magnets aremounted on the outer wall of the secondary structure; one end of the fifteenth salient pole structure is mounted on the inner wall of the primary structure, and the plurality of the windings are mounted on the plurality of the fifteenth salient pole structures. The windings are placed on the stationary side of the primary structure to make the secondary structure simple and cost-effective. In addition, the secondary structure is placed in seawater, so that the permanent magnet windings cannot be corroded, the maintenance is convenient, and the reliability is high.