MgF2 and CdSe are used to construct one-dimensional photonic crystals,and the defect layer is also introduced.The mode of electromagnetic waves in three band structures and the influence of parameters on the band gap are introduced and verified by calculation with the transfer matrix method.It is shown that there is a good reflection characteristics of MgF2/CdSe one-dimensional photonic crystal in visible band.The defect layer Ta2O5 can widen the band gap and get a good defect mode of transmission.When incident angle and thickness of Ta2O5 layers are regulated properly,the defect mode′s position can be controlled.The structure can be applied to make filter in visible band.