This paper presents the design of a dual-band terahertz metamaterial antireflection coating with a multilayered structure (two layers of metal-polyimide). The formation of the two low-reflectivity bands is analyzed by numerically calculating the electric field distributions on metal surfaces of the two layer of metal-polyimide structure. After adjusting the thickness of the polyimide layer and the size of the metal unit structure, ultra-low reflectivity is achieved with the minimum percentages of 0.0028 and 0.0025 at 0.471 and 1.560 THz, respectively (with <10% reflectivity for the bandwidths of 0.26 and 0.21 THz). The results provide a reference for the applications of multi-band terahertz metamaterial antireflection coatings.