Abstract: Local critical buckling load of friction stir welded stiffened panel under shear load is calculated by applying finite element software ABAQUS. Shear test on stiffened panel specimens is conducted to obtain the stability performance, carrying capacity of the structure and the failure load.The experiment results indicate that the failure patterns mainly contain the loosing weld of stiffener and the tearing of skin, the local buckling load of finite element calculation and test are close, and failure process of stiffened panel under shear load are simulated practically. So the finite element method is capable to analyze the stability of the structure, which offers a referenced means for the optimization design and engineering application of the structure.