Abstract: According to the test results of 5 groups of 33 simply supported steel-plate composite (SC) slabs, the deformation modes of the SC slabs are categorized into a flexural deformation mode and a punching shear deformation mode. Theoretical calculation formulas for the resistance and the stiffness are derived. The resistance function model of the SC slabs is proposed, considering the whole loading and unloading process. The accuracy of the model is verified through the existing test and numerical simulation results. Based on this model, the influence of the steel ratio, of material strength, and of connector layout on the deformation mode and on the energy dissipation capacity of the SC slabs are studied. The results show that the steel ratio and steel plate strength have great influence on the bearing capacity and on the energy dissipation capacity of the SC slab, while the influence of the concrete strength is not obvious. In order to make full use of the mechanical properties of the steel plates, the steel ratio and steel plate strength should be reasonably limited, or the arrangement of connectors should be strengthened to ensure the composite action. Since different design parameters may lead to different deformation modes and failure sequences, the design parameters should be optimized based on specific demands.