This paper presents a numerical analysis using ANSYS (18.1) finite element program to simulate the reinforced concrete slabs; six monolithic slabs and eight composite pre-slabs; Both the monolithic and pre-slabs had been supported on two edge supports to represent the case of one way simply supported slab. Fourteen slabs with length 1060mm, width 800mm, and thickness 100mm were modelled. The finite element model describes the used reinforced concrete element, the modelling of concrete, the modelling of reinforcement bars, modelling of shear connector bars and the modelling of interface element connecting the two concretes (high strength & normal strength). The results showed that the general behavior of the finite element models represented by the ultimate load, shear transfer, load-deflection curves. Show good agreement with the test results from the experimental program.