Abstract: This paper is concerned with the interface slip of steel-concrete composite beam under uniformly distributed loads. The effect of the slip on the deformation of beam is studied. Using Goodman's elasticmultiplayer assumption and elastic deformation theory, the analytical formulae of interface slip and the deformation of simply supported steel-concrete composite beam are obtained. These formulae can not onlydescribe the interface slip distribution, but also account for its effect on deformation. The present theoreticalanalysis can benchmark finite element analysis of load bearing capacity and deformation of steel-concrete composite beams.