Abstract: The fracture mechanics feature of elliptical delaminations in a composite laminate is studied. Using the method of normal slices, the relationship between stress intensity factors and energy release rate was established, based on the stress and displacement fields in the vicinity of the delamination-tip of a plane shear delamination and anti-plane shear delamination in a composite laminate. The distribution expression of the energy release rate along the front of the elliptical delamination area was obtained, combining with the total potential energy determined by the additional displacements. Computational results show the distribution of energy release rate and stress intensity factors with respect to the shape of delamination, load and thickness ratio of the laminate.