Abstract: Traditional integral methods may encounter some challenges, including massive unknowns, high storage requirements, and long computation times when calculating large-scale dielectric-metallic composite periodic structures. In this paper, the generalized Poggio-Miller-Chang-Harrington-Wu-Tsai(PMCHWT)-electric field integral equation (EFIE) method is used to calculate the dielectric-metallic structure with the contact-region modeling (CRM) technique to guarantee the continuity on the contact surface. To accelerate the filling of subarray impedance matrix, The fast dipole method (FDM) is introduced in this paper to reduce the computation time and storage requirements. Finally, the current distribution characteristics of subarrays are generalized to the composite dielectric-metallic periodic structures by the sub-entire-domain (SED) basis function method. Numerical results show that this method can significantly reduce computation time and memory usage while ensuring calculation accuracy. Compared with multilevel fast multipole method (MLFMM) of commercial software Altair FEKO, the computational memory is reduced by 1/10 and the calculation error is within 2.6 dB.