Abstract: To solve the problem of heavy weight of assembled metro station components, based on the engineering background of the first all-prefabricated metro station in Changchun Metro, the optimization design of the closed cavity structure of an assembled metro station was carried out based on the large-scale finite element software ABAQUS. Through the analysis of the whole (single ring) and the block (each component), a series of optimization measures for the closed cavity structure were put forward. Finite element numerical simulation contrast test shows:after the optimization of the closed cavity structure, the single ring structure had no substantial changes in its performance under the self-weight, and the value of each monitoring index was far less than the specification limit. The structural weight decreased by 18.5%, and the internal forces of the structure were reduced to different extents. The effect on the bending moment was the greatest, the shear force was the second, and the axial force was the smallest. Its trend was beneficial to the structure. The test verified the safety and reliability of the closed cavity structure.