Abstract: This article mainly studies the structural design of multi-layer steel structure modules and steel frame composite buildings. By combining with a building project in H City, the multi-layer steel structure design scheme adopted by it is analyzed, and the calculation of structural parameters and simplified design of joints are adopted. As well as the method of model analysis, the best steel structure modular design plan can be obtained, which can improve the design quality of the multi-layer steel structure of the construction project, solve the problems existing in the steel structure design of the current part of the project, so that the quality of the steel structure of the construction project has been comprehensively improved. It has made certain innovations in the design of multi-story steel structures in buildings, hoping to promote my country's architectural design industry.