Abstract: Through the compression, bending and tensile tests of composite laminates with delamination defects, the influence of the depth of delamination defects on the mechanical properties of the laminates was studied. The factors affecting the mechanical properties of the laminates were qualitatively analyzed, and the variation law of the mechanical properties of the laminates with the depth of delamination defects was obtained. The results show that the depth of delamination defects had a direct effect on the compressive and bending strength of laminates, but had a limited effect on the tensile strength.