Photonic crystal is an optical microstructure whose dielectric constant is periodically modulated by spatial position. The structure of photonic crystal can be divided into one-dimensional, two-dimensional and three-dimensional, and two-dimensional has become a research hotspot. For the photonic crystal doped with tin oxide in two-dimensional hexagonal graphene, this paper uses COMSOL software to solve the energy band of the lattice on the basis of triangular cell, and obtains the electric field height image and energy band structure diagram under TM and TE modes. The localization of the electric field and the band gap structure of the two modes in a certain frequency range are analyzed. It provides a simulation method and theoretical basis for the application of this material.