Abstract: A model for analyzing the interface slip of steel-concrete composite beams is presented in this paper. In the model, the total moment of the composite beam with interface slip consists of the local moment carried by superposition beam with free interface slip and the global moment carried by the composite beam without interface slip. A method to calculate the distribution of the section moment and the shear force is established. The formulas for the intersection slip in the global-local model and those for the cross section stress and deflection of the beam considering the slip of interface are obtained based on Bernoulli beam theory and the linear shear-slip model of the shear connector. As an example, the shear force of the bolt-connector and the interface slip are given for simply supported beams under concentrated loading.