Abstract: A 2-dimensional finite element stiffener model is developed,which is equivalent to real stiffeners in stretch and bending stiffness and can be applied to analysis of a stiffened structure with cracks, A sufficient-necpssary condition is put forward, which assures the stiffener model equivalent to real stiffeners in stretch stiffness. A formula for reduced cross section area of a stiffener is presented, which can be used conveniently for different stiffencrs.