Abstract: Taking simply supported steel-concrete-steel sandwich beam an example, this paper focused on constructing a simplified calculation model of steel-concrete-steel sandwich beam under concentrated load, equations illustrating interface slips between steel and concrete and deformations were obtained based on proposed analysis model. The deduced equations can not only describe the deformation distribution of slipping interface, but also reflect the deformation of composite beam influenced by interface slips. The computed results using the formulas of this paper are in good agreements with the experiments results in literature. Example study shows that, as applying loads and shear connectors span increase, both of interface slips and bending deformations rise significantly.