The goal of this thesis is to shed light on the elastic properties, especially the Young modulus, of clinker phases and hydration products of cement paste through molecular dynamic simulation by COMPASS force field. The parameters that can affect the elastic properties of cement phases were also targeted, with special attention paid to analog C-S-H minerals, in which the Tobermorite family and Jennite were simulated to render their structures representative of C-S-H structure. The molecular dynamic simulations of this study show that CO force field can be applicable for most clinker phases and hydration products. Jennite, with its porosity and finite silicate chain accounted for, can be considered the closer and representative structure of C-S-H. In addition, this study confirms the important effect of C/S ratio, packing factor and chain length on elastic properties of C-S-H.