The adsorption of NO molecules on Mn-doped CeO2 (111) surface for NO oxidation has been studied by employing periodic density functional theory plus U (DFT+U) method. Through our calculations, it is demonstrated how Mn-doped CeO2 with superior NO oxidation activity benefits from the high mobility of the oxygen near the Mn cations. On unreduced Mn-doped CeO2 (111) surfaces, NO molecule preferentially interacted with the first neighbor O of the Mn cations, with the N also bonded to Mn cation (Eads = –3.30 eV) or Ce cation (Eads = –2.90 eV). When NO adsorbs on the surface of defective Mn-doped CeO2 with O2 adsorbed in advance, an ONOO* four atoms species are formed on surface (Eads= –2.51 eV and –2.02 eV), which is a reaction intermediate and can decompose to NO2, NO2* and O*. Adsorption structure with higher adsorption energy, has a closer geometry to NO2, indicating a deeper oxidation of NO. The calculation results indicate that the presence of Mn only has a strong effect on the nearby oxygen atoms, and Mn-doped CeO2 surface has a similar property to the noble metal in NO oxidation catalysis. In DOS plots, the spin of the electron state of the adsorption structures involving oxidation of NO is symmetric, indicating that electron transfer occurs from the slab to NO and strong covalent bonds are formed between N and O on the slab, which can also be confirmed by the charge density difference plots.