A new way for designing one-dimensional photonic crystal, which has double-channel, is given by researching the characteristics of Fabry-Perot filter and analyzing the influence of thickness change of defect layers on the number and the position of the channels. A double-symmetrical structure consisted of one-dimensional photonic crystal is introduced based on the Fabry-Perot structure. The position of the two channel series in the photonic forbidden band is separately adjusted by changing the thickness of three defect layers in the double-symmetrical structure. The equivalent surface method is used in the elementary calculation and the computer simulation is used to further modify the thickness of the layer. With this design, the interference of different channels is avoided and the independent change of the channel position is realized in the double-sysmmetrical one-dimensional photonic crystal.