The elastic modulus of saturate concrete is investigated in this paper. Based on micromechanics of composite materials, the elastic modulus of saturate concrete is obtained by considering the deformation of both pore and microcracks in concrete. It is assumed that concrete deformation includes the contribution of concrete matrix, pore water and microcracks. The water viscosity between microcracks and the further hydration of cement are both taken into account too in this paper. The comparison between the results by the model proposed in this paper and by existed experiments indicates a favorable agreement.