Abstract: In order to predict the post-buckling loading capability of omega stiffened composite panel accurately, the failure mechanism and failure load of omega stiffened composite panel with tapered stringers under compressive load were investigated. Firstly, the failure process of stiffened panel with tapered stringers was explored based on specimen experiment, and a nonlinear progressive damage model with the failure of adhesive interface and composite laminate was established to study the damage initiation and failure process in detail. Then, the method for the skin/flange interface enhanced by cladding layer was proposed, and the influence of the cladding layer on the failure mode and carrying capability has been explored by numerical simulation and test. The results show that the buckling load and post-buckling loading of the panel reinforced by cladding layer increase significantly. Moreover, the FE results for loading capability and the failure mode coincide with the test results.