In this study, FE analyses are performed for stiffened plates with a flat-bar or deep tee-bar under axial compression, the characteristics of the torsional deformation of the stiffener is clarified. The analytical solutions based on elastic large deflection analysis are derived to simulate the elastic behavior of an isolated stiffener under axial compression. It is confirmed that the elastic behavior has a sufficient accuracy. The method for the stiffened plate is also proposed. The elastic behavior in the case with the flatbar is simulated with a sufficient accuracy, while the accuracy in the case with the deep tee-bar is not sufficient. However, it is acceptable to estimate the ultimate strength. The ultimate strength of the stiffened plate with the deep tee-bar is estimated using the analytical solutions. The estimated strength has a good correlation with that obtained by FEA, and it is found that the proposed method is beneficial.