Theoretical and experimental investigations have demonstrated that full bandgaps are not easy to achieve in the face-centered cubic (fcc) unary and binary structures; even for unary inverse opals with high refractive index network, the bandgaps are not as large as 1D or 2D structures. In this work, we simulated the bandgap of a binary inverse opal, which is over 16% larger than that of a unary inverse crystal. Two kinds of binary colloidal crystals and their inverse structures have been fabricated by a horizontal deposition method.