Abstract: The effect of stitching on mechanical properties of sandwich structures using vacuum infusion was investigated. The failure modes of the sandwich structures through lateral compression were explored.Resultsshow that the mechanical properties of sandwich structure composites can be significantly improved by stitching. The the side pressures and moduli in length and width directions of composites reinforced in two directions are same. The side pressures and moduli of the composite reinforced in one direction have directivity, and the modulus in the length direction is significantly higher than that in the width direction.