Staggered truss structure is a new type of fabricated steel structure system with the characteristics of large span, large space, large stiffness and good economy. However, due to its unique structure, the calculation method of the fabricated staggered truss structure system is completely different from the traditional steel frame structure, especially the assumption of the floor has a great influence on the overall calculation of the staggered truss structure system; and how to consider the influence of the construction on the plane truss in the calculation and analysis of the fabricated staggered truss structure in the design stage is also the control index. Based on the analysis of the key technology of staggered truss structure, and combined with Hangzhou Xiaoshan International Airport No. 5 and No. 6 apartment building project as an example, this paper focuses on the truss layout and floor calculation of staggered truss structure in the process of design and construction, as well as the elastic response spectrum method analysis and static elastic-plastic analysis of the project, and explores the plastic development mechanism of staggered truss structure. The research shows that the simplified floor calculation model solves the calculation problems in the design stage of staggered truss, and it is a kind of modeling calculation method that can be directly applied; and through the comparative analysis of two finite element analysis software of etbas and YJK, the fabricated staggered truss structure of steel structure has good energy dissipation mechanism and seismic performance, which is worthy of popularization and application Structure system.