Most building structures consist of main structures such as beams, columns, braces, shear walls, foundation, and floors. Generally, the seismic performance of the floor slab to the building structure is negligible; therefore, analysis models of building structures do not consider floors, and the floor slab is replaced by a rigid baffle to increase the analysis efficiency. The seismic analysis model of building structures proposed in this paper considers the bending stiffness of the floor. The model uses super element, rigid baffle, and substructure technique to reduce the degree of freedom. Through an example analysis, the validity and accuracy of the model in the seismic analysis of multi-story building structure are verified. The proposed model can significantly reduce computational complexity and improve analysis efficiency. Moreover, the accuracy of the analysis results, such as the vibration cycle and response time, is very close to the result of the refined model, which substantiates the efficiency of the proposed model.