A symmetric photonic crystal composed of TiO2 and SiO2 was designed, and its transmission spectrum was calculated with the method of transfer matrix by taking consideration of the dispersion relation. The results indicate that there is only one transmission peak with narrow half width and the transmission rate value of 1 in the frequency range of 0.8~1.2ν/ν0. When the incident angle increases, the center frequency of the transmission peak will present blue shift with constant peak value and basically invariable half width. Thus the corresponding photonic crystal filter has excellent transmittance, good monochromaticity and better angle tolerance, therefore it is more suitable with the situations with small angle of incidence.