Abstract: In order to study the effect of stitching on the flexural properties of foam sandwich panels,three groups of test specimens,including non-stitched test specimens,improved lock stitching and tufting stitching test specimens,are selected to carry out experimental research and flexural performance analysis of the sandwich panel. The results show that the flexural properties of the composites can be improved by properly optimizing the stitching density,and the flexural properties of the composites with medium stitching density are better.