In this paper, a high reflector based on one-dimensional photonic crystal of hetero-structure in infrared region(3-5 μm) is investigated. The reflection characteristics of light wave in one-dimensional periodic photonic crystals are systematically analyzed. The reflectivity and the optimal forbidden band width of the λ/4 dielectric film system are verified by transfer matrix theory calculation and simulation. On this basis, Si and Y2O3 are selected to construct the one-dimensional photonic crystal of double hetero-structure with 24 layers. The simulation result shows that the reflectivity in infrared region (3-5 μm) is between 97.418% and 99.999%. In order to reduce the number of the film layers, using metal silver as an substrate, we design the dielectric layer structure of Si and Y2O3 with 9 layers of one-dimensional metal enhanced photonic crystal. The simulation result shows that the reflectivity is between 98.943% and 99.979% in the infrared band of 3-5 μm.