Abstract: The presence of damage in a structure could considerably affect its behaviors. This paper studied the dynamic stability behavior of a damaged stiffened-plate subjected to an in-plane compressive periodic edge load by the finite element method. The influence of parameters such as extent, size and position of damage was discussed. Considering the coupling effect of vibration and buckling, numerical analysis of typical examples was carried out. It shows that the presence of damage had a marked effect on the dynamic instability regions.