This work aims to validate and assess the MODIS-derived bidirectional reflectivity retrieval algorithm in mid-infrared (MIR) channel, proposed by Tang and Li (2008), with ground-measured data, which were collected from a field campaign that took place in June 2004 at the ONERA (Office National d’Etudes et de Recherches Aérospatiales) center of Fauga-Mauzac, on the PIRRENE (Programme Interdisciplinaire de Recherche sur la Radiométrie en Environnement Extérieur) experiment site (Kanani et al., 2007). The leaving-surface spectral radiances measured by a BOMEM (MR250 Series) Fourier transform interferometer were used to calculate the ground brightness temperatures with the combination of the inversion of the Planck function and the spectral response functions of MODIS channels 22 and 23, and then to estimate the ground brightness temperature without the contribution of the solar direct beam by using Tang and Li’s proposed algorithm. On the other hand, the simultaneously measured atmospheric profiles were used to obtain the atmospheric parameters and then to calculate the ground brightness temperature without the contribution of the solar direct beam, based on the atmospheric radiative transfer equation in the MIR region. Comparison of these two kinds of brightness temperature obtained by two different methods can indirectly test and validate Tang and Li’s land surface bidirectional reflectivity retrieval algorithm. The results showed that the Root Mean Square Error (RMSE) between the brightness temperatures estimated respectively using Tang and Li’s algorithm and the atmospheric radiative transfer equation is 1.93 K. It affects the retrieval accuracy of the land surface bidirectional reflectivity in the MIR less than 0.002.