Abstract: This paper addresses the design issues and target requirements of a large-span CAVE screen steel keel structure with a width of 24 m for the Mogao Grottoes. First, a modular design approach is adopted to establish the theoretical model of the CAVE screen steel keel structure. Second, finite element simulation analysis of the top base ring support is carried out using the Simulation module in SolidWorks. The results show that the stiffness and strength of the top base ring support meet the design requirements. Finally, on-site installation and three-dimensional laser scanning verification demonstrate that the designed large-span CAVE screen steel keel structure satisfies practical application requirements. In conclusion, the modularly designed large-span CAVE screen steel keel structure is proven to be feasible.