The influence of the two dimensional photonic crystals on the absorption of materials and the substrate is studied. By using the transfer matrix method along with a certain direction of lattice photonic crystal, the energy band structure based on the transfer matrix method is solved. Researches show that absorption can bring new band gap to a frequency which doesn′t have band gaps, while extending the range of the original band gap, and TE wave is more impacted than TM wave by the absorption.