A one-dimensional photonic crystal mode based on TiO2/SiO2 multilayer films with defect state is designed. The properties of the defect mode dependent on the numbers of base layer cycle, defect layer locations, optical thicknesses, and materials have been theoretically and systematically studied by simulation using the FDTD (Finite Difference Time Domain) method. The results show that the transmittance and width of the defect mode are greatly related with the numbers of base layer cycle, the defect layer locations and the materials, while the location of center wavelength only depends on the optical thickness of the defect layer.