The　α-Fe2O3　nano-wires　were　grown　on　99%　pure　iron　substrates　by　thermal　oxidation　in　air.　The　impacts　of　growth　conditions,　including　the　oxidation　temperature　and　time,　on　its　microstructures　and　emission　properties　were　evaluated.　The　nano-wires　were　characterized　with　X-ray　diffraction,　and　scanning　electron　microscopy.　The　results　show　that　the　oxidation　temperature　and　time　strongly　affect　the　microstructures　and　emission　characteristics　of　the　nano-wires.　For　instance,　at　600°C,　the　(110)　and　(300)　preferentially　oriented　nano-wire　were　obtained.　For　a　short　oxidation　time,　the　nano-flakes　dominated;and　as　the　time　increased,　the　nano-wires　gradually　showed　up,　growing　in　number　and　in　length.　The　aspect　ratio　and　density　of　the　nano-wire,　grown　at　400°C　for　4　h,　were　found　to　be　optimal　for　field　emission,　with　an　on-set　field　of　2.3　V/m　and　a　fairly　uniform　and　stable　emission.