The postbuckling behavior of laminated composite cylindrical panel with T-type stringer was analyzed using the finite element program developed. In order to examine the interaction of panel and stringer and the interaction of web and flange forming stringer. the eight node degenerated shell element same as the panel element was utilized as the stringer element. In the nonlinear finite element formulation. the updated Lagrangian scheme based on the second Piola-Kirchhoff stress and the Green-Lagrangian strain was used. In analyzing the failure characteristics, the progressive failure analysis was adopted. The postbuckling experiment of the laminated composite cyrindrical panel with blade-type stringer was done to verify the finite element analysis. As the web and flange sizes were increased. both the buckling load and the postbuckling ultimate load grew. Most of the failure occurred near the intersection of panel and stringer. The failure of stringer disabled the panel from carrying additional loads, and the structure collapsed immediately.