Interaction of O2 molecule and a zigzag aluminum nitride nanotube(AlNNT) was studied based on the density functional theory.The O2 molecule is adsorbed on the surface of AlNNT with the adsorption energies in the range of 11.0 to 12.1 kJ/mol.Geometrical structure of the AlNNT remains intact in the presence of oxygen molecule while its electronic structure dramatically changes so that its HOMO(or SOMO)-LUMO gap is approximately reduced to half of its original value.It suggests that the AlNNT may be used as a gas sensor for the O2 detection. Interaction of O2 molecule and a zigzag aluminum nitride nanotube (AlNNT) was studied based on the density functional theory. The O2 molecule is adsorbed on the surface of AlNNT ​​with the adsorption energies in the range of 11.0 to 12.1 kJ / mol. Geometrical structure of the AlNNT ​​remains intact in the presence of oxygen molecule while its electronic structure plays makes it its HOMO (or SOMO) -LUMO gap is reduced to half of its original value. It suggests that the AlNNT ​​may be used as a gas sensor for the O2 detection.