Abstract:In order to quantitatively reveal the combination of steel and concrete interface, an analysis method was provided for the calculation of composite girder considering connectors, bond stress and friction in the interface between the steel and the concrete. The feasibility of the method was also verified through the experiment. This method was used to analyze the relationship between different steelconcrete connecting conditions and interface slip and also the effect of the present or not of the interface bonding on the mechanical behavior of the composite girder was analyzed. The results show that, the steelconcrete interface bonding effect has a tine effect on the stress of the concrete slab and steel girder, but has a large effect on the shear force of the connectors where the maximum effect can reach 25 percent under different loads.