A kind of one dimensional three element photonic crystal with symmetrical structure has been designed.The polarization filtering properties have been studied by using the transfer matrix method. It is found that the separation degree of band gap and resonance mode of two polarized waves increase with the increase of the incident angle and medium thickness,and the increase of the period number N has obvious influence on the separation degree of the two polarized waves,while the change of the symmetry degree of the crystal structure has little effect on the separation degree of band gap and resonant mode of the two waves.