The invention relates to a closed skeleton structure applied to spiral seaweed production. The closed skeleton structure comprises a skeleton and a shielding layer which covers the surface of the skeleton. The closed skeleton structure is arranged on skeleton foundations on the periphery of a spiral seaweed pool body. The skeleton is composed of a plurality of arched support units and further comprises an electric sunshade net assembly. A gutter is formed at the arch connecting position of each two adjacent arched support units in the axial direction. A rainproof seal assembly is arranged at each gutter. The closed skeleton structure is sturdy, durable and capable of providing a good living environment for spiral seaweed. The closed skeleton structure has the advantages of being anti-erosion, anti-aging, high in light transmittance, good in heat retaining property and sealing, heat-insulating, fire-retardant, light in weight, easy to assemble, detachable, convenient to use and low in cost, and having no use for frequent replacement of a covering, and can not release poisonous gas under the conditions of illumination and high temperature. The growth rate of the spiral seaweed is increased, the number of dead seedlings is reduced, a growing period of the spiral seaweed is prolonged, and a yield is improved.