In the COVID-19 epidemic sweeping the country, assembled box wards have been widely used in the fight against the epidemic. It is crucial to ensure the completion of hospital construction on time and meet the needs of medical procedures in infectious disease hospitals. Based on BIM technology, this paper combines the steel structure box-type modular wards of Huoshenshan Hospital and Leishenshan Hospitals in Wuhan, optimizes the design of the modular box room, and designs a modular ward with complete functions, fast assembly, and collapsible disassembly. By folding and optimizing the main body of the steel structure, the reformed components are produced in the factory and can be installed directly on the construction site. The optimized design is convenient for transportation and fewer installation procedures， which is conducive to the rapid construction and installation on the site.