The calculations performed in this article were performed using the Dmoi3 package.The properties of (Fe2O3)n(2≤n≤6) clusters and adsorption of NO molecule on them have been studied by the Perdew-Burke-Ernzerh(PBE) generalized gradient approximation(GGA) and the double-number polarization functions of DNP with the Dmol3 program in Materials Studio package based the density functional theory (DFT).The optimized results indicated that the Fe-O bond of all the clusters was shorter than the bulk material while the binding energy of all the ground state of clusters was larger than the average energy of Fe2O3 So the structures and bonding properties of the clusters are different from the bulk Fe2O3.The frontier molecular orbitals and Fukui function analysis indicated that the best adsorption sites of (Fe2O3)n clusters are Fe sites.NO adsorption with N-down on the Fe-(Fe2O3)n sites are chemisorption and resulted in favorable structures with adsorption energies of 1.792、 1.976、 2.799、 2.963 and 2.536eV, respectively.An analysis of the density of states, charge population before and after the adsorption showed that electrons transferred from NO to the surface of the (Fe2O3)n(2≤n≤6) clusters and that the N-O bond was elongated.The interaction between the adsorbed molecule and the substrate mainly arises from the 2π anti-bonding orbital of NO and the d orbital of Fe atom.NO lose electrons under the joint action of 2π antibonding orbitals get electrons and its 5σ orbitals lose electrons.