The interaction between steel I-beam and concrete slab largely influences the overall behaviour of the composite beam. An effective model should combine a suitable group of finite elements to represent both of the shear connectors and the beam-slab interface as well as the concrete slab and the steel beam. In this paper, a three dimensional finite element model is presented to simulate the global behaviour of composite beams subjected to negative bending moments, where the studs uplift and slippage were modelled accurately. This modeling is valid also for composite beams under positive moments. The materials non-linearity was taken into account. The results of the introduced model are compared with literature experimental tests where a good agreement was reported.