This paper studies the local stiffness determination method in cracked regions to apply continuum mechanics to the cross-ply composite plate with delaminations and matrix cracks, subjected to transverse and in-plane loads.The plate is divided into adequate regions according to crack distribution density and then strain energy in each element (region) is computed from complementary energy by cracks in that element. Matrix cracks are of the mode I, II, III and thus corresponding stress intensity factors are calculated. The stiffness of element in the cracked region, i.e. the local stiffness is determined from the Green’s theorem using the obtained strain energy.The simply supported cross-ply composite plate with matrix cracks and delaminations under transverse and in-plane loads is analyzed by using the obtained local stiffness in the ANSYS APDL. The availability of the proposed method based on crack modeling and local stiffness is evaluated through comparison.