Abstract: The deformation and failure of welded joints in the typical sandwhich panels have been studied by means of the shearing test and the T-joint bending test,combining with FEM simulation. The results show that during bending process,the welded joints between front panel and web panel are mainly subjected to shearing and bending moment parallel to the front panel. With load increasing,there is damage initiation at the weld root,along with a deep expanding cracking path. Aimed at the failure analysis of welded joints,experiments have a good agreement with numerical results.