The research on the surface emissivity directionality is a hot and difficult issue in the international thermal infrared quantitative remote sensing area. The existing emissivity directional models for sandy area in thermal infrared bands have some disadvantages, such as too many prior parameters, low accuracy and poor applicability. Therefore, with the aid of long-time series (2018-2020) multi-angle observations from geostationary-orbit MSG/SEVIRI and polar-orbit AQUA/MODIS, after data pre-processing related to inter-sensor calibration, atmospheric correction, spatial and temporal matching, we retrieved the directional emissivity under different viewing zenith angles (VZAs) between 0~65°over five pseudo-invariant calibration sites based on the thermal infrared radiation transfer equation, including Algeria3_1km, Algeria5_1km, Libya1_1km, Mauritania1_1km and Mauritania2_1km. Subsequently, a model for retrieving the kilometer-scale directional emissivity was established, and its uncertainty was evaluated. The result shows that the surface emissivity decreases with the increase in VZA, and the directional effect decreases with the increase in the MODIS band central wavelength; Algeria5_1km has the smallest directional effect, and Mauritania1_1km has the strongest effect, the uncertainty of the directional emissivity model in each region increases with VZA, and is better than 3%.