Functional devices operating in the terahertz band often use high refractive index materials such as silicon and germanium as interfaces, which can cause impedance mismatch between the interface and air, thus leading to unnecessary loss of light energy. Plating an antireflective coating at the interface can effectively reduce reflectivity and increase transmittance, thereby greatly improving the performance of the device. Therefore, the development of antireflective coating is of great significance. Considering the above requirements, the research significance of terahertz antireflective coating is first introduced, and then several common methods for preparing terahertz antireflective coating at home and abroad are presented, and the advantages and disadvantages of each are analyzed. Finally, the research on terahertz antireflective coating is summarized along with future prospects.