a-Fe2O3 nanowire was successfully synthesized by oxidation of pure iron. The as-synthesized a-Fe2O3 nanowire arrayed normal to the surface of the substrate, were perfect single crystals with diameters of 20 to 40 nm and lengths varying from 2 to 5 µm. The magnetic property of the nanowires was studied, and some interesting phenomena were observed. The magnetic moment of the nanowire shows an antiferromagnetic behavior at high temperature and a weakly ferromagnetic behavior at low temperature. The block temperature of the a-Fe2O3 nanowire was found to be significantly higher than that of a-Fe2O3 nanoparticle.