In this paper, a hybrid algorithm based on nonoverlapping domain decomposition method and surface Integral equation (SIE-DDM) is presented for dealing with time-harmonic electromagnetic (EM) problems of dielectric or composite object. The proposed method divides the composite object into homogeneous, non-overlapping sub-domains. Robin transmission condition is introduced to weakly enforce the continuity of tangential field across the touching-face between adjacent subdomains. Here, the electric and magnetic current combined-field integral equation (JMCFIE) is used for each sub-problem. The accuracy, efficiency, and meshing flexibility of the proposed method have been demonstrated by numerical results.