When designing a very thin stiffened panel subjected to axial compressive loading beyond its buckling strength, post buckling behaviour of the panel should be taken into consideration. Allowing the panel to buckle would raise two important strength aspects to be considered. One is the ultimate strength of the panel and the other is the fatigue strength of the welded panel boundaries (welded part of stiffeners) due to cyclic buckling deformation. Many researches have been conducted regarding the ultimate strength, and characteristics of panels under static axial loading have been well clarified up to the ultimate strength. Regarding the fatigue strength, however, very little is known in the field of welded ship structures. In this paper, with the help of non-linear (elasto-plastic and large deflection) finite element analysis and the modified Miner's law, characteristics of a very thin stiffened panel subjected to cyclic axial compressive loading beyond buckling strength is studied.