Abstract: In this paper the development of damage mechanics of composite materials and the damage strain enefgy release rate (y) failure criterion are presented briefly. In order to further verify the applicability of the damage strain energy release rate criterion, the authors carried out uniaxial tensile damage tests on two commonly-used graphite/648 epxy laminates-[0/90] and [0/±45/90] using about 120 specimens with different shapes and sizes of initial notches. All of these experimental results varified that the damage strain energy release rate failure criterion does reflect the failure regularity of composite laminates.