Modular steel structure with a 100% assembly rate, is one of significant methods to realize building industrialization. It has an extensive application prospect due to the short construction cycle and small impact on the surrounding environment.. Based on the characteristics of modular architecture, this paper takes the work of the 2018 Chinese College Students Steel Structure Innovation Competition as an example to discuss the design possibilities of student dormitories. However, due to production mode and transportation conditions, modular building also has some limitations for application. Through research on design, this paper makes the breakthroughs in the design limitations of modular building.