Based on the first principle calculation, the catalytic performance of a cheap metal Fe doped hexagonal boron nitride (Fe-BN) for N2O reduction in the presence of CO or SO2 was studied. From the analysis of the adsorption configurations and electronic properties, it was found that the spontaneous dissociation of N2O on the surface of Fe-BN was caused by a large amount of charge transfer between the substrate and N2O. The adsorption energy of N2O was much greater than that of CO or SO2, which would be conducive to the reaction. The reaction energy barriers of CO, SO2 and N2O with O* were calculated to be 0.52 eV, 1.06 eV and 2.61 eV, respectively. The reaction energy barrier of N2O was the highest, indicating that this reaction could not occur. The adsorption of the reaction product CO2 by Fe-BN was weak, and the energy released through the reaction process could satisfy the desorption of CO2, while the desorption of SO3 could not occur. So it can be seen that CO is more favorable as a reducing agent. It is concluded that Fe-BN is a highly active catalyst for N2O reduction. This study opens up a new way for the development of low-cost and highly active catalysts based on low-cost metal doped hexagonal boron nitride.