Abstract: The adsorption behavior of active gases in the air on the surface of Pu-based materials is an important cause of surface corrosion of Pu-based materials. The adsorption behavior of N₂ and O₂, two main gases in air, on δ-Pu(100) surface is studied using the first principle method. The Bader charge analysis and the adsorption energy and binding energy analysis of all stable adsorption configurations show that the most stable adsorption configuration of N₂ molecule is H-S-N6 and the most stable adsorption configuration of O₂ molecule is H-P-O4. The results of differential charge density analysis, density of states analysis and COHP calculation show that the adsorption of N₂ and O₂ on δ-Pu(100) surface is strong chemical adsorption, and the adsorption of O₂ is much stronger than that of N₂. Furthermore, the bonding essence is that the 2s and 2p orbitals of N atom or O atom overlap with the 6p, 6d and 5f orbitals of Pu atom on the surface. These results can be a good foundation for the study of the co-adsorption behavior of N₂ and O₂ on δ-Pu(100) surface and are of great significance for revealing the surface corrosion mechanism of plutonium materials in air.