Abstract: The complex refractive indexes of β-FeSi₂ and Si in the visible and near-infrared (NIR) are analyzed, and the simple structures of three-layer film have been designed. The structures consisting of Si and β-FeSi₂ are Si/β-FeSi₂/Si with three different parameters. The thickness of Si in the top layer is variable, but both the thickness of β-FeSi₂ in the middle layer and the thickness of Si in the bottom layer are fixed. In the visible and NIR range, both Fresnel theory and the method of finite element numerical analysis have been used to analyze the optical transmission of these structures with normal incidence, and the physical mechanism has been explained. The material Si has a huge anomalous dispersion with about dn/dλ=30.5 μm^-1 in the wavelength range from 0.30 μm to 0.37 μm, and the β-FeSi₂ has larger anomalous dispersion with dn/dλ=5 μm^-1 in the wavelength range from 0.30 μm to 1.10 μm. The results show that the simple design can be applied in many photodevices, and indicate that the properties, such as reflectivity and transmissivity, can also be flexibly adjusted by changing the thickness of Si in the top layer. When the wavelength is in the visible range or the NIR, the transmissions and reflections of the designs have the sharpest differences, respectively. The structures of the three layer films are straightforward, and their properties have been easily adjusted by changing the thickness of the top Si layer.