Abstract: An equivalent electromagnetic model was established in this study based on the electrical structural features of periodic porous structural materials. Through simulation and calculation, the influence rules of the lattice cell shape, loading method, and structural size on the electromagnetic performance in dual polarization were obtained. The influence mechanisms of the unit wall thickness and the included angle of the lattice cells on the equivalent permittivity were comprehensively analyzed. By adjusting the equivalent permittivity through the lattice cell side length and combining with the optimized design method for impedance matching, the periodic porous material achieved good electromagnetic performance across a wide frequency range and exhibits good electromagnetic consistency for dual polarization. The results show that: if the periodic porous structure lacks inherent bilateral symmetry but its electrical structure satisfies bilateral symmetry, good electromagnetic consistency for dual polarization can be obtained. For the typical hexagonal lattice cell structure, when the thickness of the straight side wall equals that of the oblique side wall, good electromagnetic consistency for dual polarization is achieved, and reducing the wall thickness can further improve it. If the wall thickness is fixed, good electromagnetic consistency for dual polarization can be obtained by optimizing the included angle of the lattice cells. By optimizing the electrical structure, the maximum mean deviations of the real and imaginary parts of the equivalent permittivity under dual polarization are 0.063 and 0.053, respectively, with the material showing good electromagnetic performance in the 2–18 GHz band. The research results provide support for the subsequent optimization of the electromagnetic performance of dual-polarized periodic porous materials.