SiO₂ and CdSe are used to construct one-dimensional photonic crystal in visible region,including the introduction of LiTaO3 defect layer.The formation of photonic band gaps is exhibited and confirmed by a calculation of the transfer matrix method (TMM).There becomes defect modes in the photonic forbidden band gap compared with the photonic crystals without defects.The position,amount and reflection properties of the defect modes are related with the form of defect and the thickness of defect and periodicity of photonic crystals.It is shown that the variety of the width of impure layer in one-dimensional photonic crystal and the periods number layers of photonic crystal can alter the transmission,the location and numbers of photonic defect mode.When the thickness of LiTaO3 inserts layer is regulated properly,for instance,the defect module can be appeared on red light,yellow light area of visible region.The structure should enable new applications for photonic crystal devices design.