Abstract: The compressive properties of composite honeycomb sandwich plates containing interface delamination defect between the facesheet and the core at the plate center were experimentally studied and theoretically analyzed.The influence of one circular delamination and two rectangular delamination defects on the compressive strength was discussed. A sub-laminate local buckling model was used to estimate the compressive strength of the sandwich plates. The results show that general buckling of the sandwich plates without any defects causes the final compression failure. But for the sandwich plates with delamination defect，there are different failure mechanisms with different delamination shapes and sizes. In general，facesheet local buckling cannot play a controlling role in the sandwich plate failure when the long side of the rectangular defect is vertical to the load direction. While the plate exhibits general buckling failure when the long side of the rectangular defect is parallel to the load direction. The sub-laminate local buckling model is effective to predict the compressive strength of the sandwich plate containing delamination defect while the facesheet local buckling acts as a controlling factor .