FRR(fiber reinforced rubber) is a flexible material which consists of elastomer and helical cord. The purpose of this study is to propose a simplified mechanical model for an estimation for extensional stiffness of a FRR column. At first, FEM analysis is performed for the FRR column. The mechanical behavior of the FRR column depends on the helix angle, fiber diameter and pitch circle diameter of the helical cords. The incompressibility of the elastomer, which is located at the center of the FRR column, has also an important effect on the mechanical behavior. Secondly a mechanical model is proposed on the basis of the FEM results. The simplified model reasonably explains the deformation behavior of the FRR column.