Objective In order to solve the problem that infrared anti-reflection film is valid only on a certain wave length or angle. Methods Three kinds of structures, containing nanometer raised structure, nanometer pore structure and nanometer grating structures, were designed based on sapphire material by FDTD method to realize transmission enhancement in 0.7~5 μm near-infrared and mid-infrared region. To optimize the height, width and spacing of the surface microstructure unit, their influence on transmission was analyzed through adjusting geometric parameter and unit configuration. Results Simulation results showed that with the other geometric parameters fixed, all of the three kinds exhibited enhanced light transmission phenomenon with an increase in cell height and gradually trended to be stable as the height increases. With cell height in its best condition, the best transmission characteristics were obtained when the three structures were close to or slightly above the bottom of the cell gap width. Beyond this range, the transmission characteristic decreased with increasing cell width. Therefore, in order to achieve a good antireflection effect, attention should be paid to the structure of each unit interval during the manufacturing process. Conclusion By virtue of comparison among the three kinds of five nano-structures, it is indicated that nano-grating structures own the best transmission enhancement quality under equal parameter conditions.