In this paper, a novel CdTe gratings structure is designed aimed at constructing omnidirectional infrared nonreciprocal absorbers at wavelength from 18 mu m to 23 mu m. CdTe is a commonly used semiconductor infrared film material, which is widely used in photovoltaic, infrared detection, fluorescence and other applications. The optical radiation characteristics of magneto-optical material CdTe are studied based on the Lorentz-Drude model, which is verified with the optical constants in handbook. The time-domain finite difference (FDTD) method was used to calculate the infrared radiation characteristics of CdTe gratings, and the electric field square modulus distribution with different wavelengths is presented. It is found that the nonreciprocal absorptivity is obvious as the incidence angle is 45 degrees at the positive and negative angles. The effects of magnetic field strength, grating thickness, incidence angles on the optical properties, especially the non-reciprocity are analyzed in details. The numerical simulation results are useful to the thermal radiative design in infrared absorber and other optical instrument. (C) 2019 Elsevier Ltd. All rights reserved.