<p>Today, a vast range of offshore structures is used in different parts of the world. Computing the force on an offshore structure is one of the first measures for designing the structure and also one of the most difficult steps in the design process. Most of offshore structures are considered as large structures. In these cases, it is used from diffraction theory for computing the imposed force. Using cylindrical elements is common in construction these structures. In this study, the effect of incident wave&rsquo;s deviation angle on the force on the unit length of one elliptical vertical cylinder located within deep waters examined with finite element method. The obtained results show that the used numerical method had acceptable accuracy and the surge force on the vertical cylinder decreases with deviation angle increasing and consequently the sway force increases.</p>