Abstract: Tensile test for honeycomb sandwich plates and foam sandwich plates was carried out by the tension of fixture to simulate shear damage behaviors. The distribution of strain field and the reason for failure were revealed by the analysis of the load-strain curves and failure mode. In addition, the shear behaviors of different composite sandwich plates were simulated by finite element software. The results show that the both failure modes were all buckling failure along the loading direction, and the region between the middle part and boundary part was a pure shear region. The horizontal shear modulus of different cores had a great influence on the buckling load and failure mode. And the finited element simulated buckling mode of sandwich plates fitted well with that from the experiment.