Abstract: The behavior of corrosion resistance to simulated exhaust gas of Fe-28Al-5Cr, Fe-28Al-5Cr-0.5Nb-0.1C and GTA (gas tungsten arc) welded Fe₃Al based alloys has been investigated. The composition and emerging mechanism of corrosion scale have been analyzed, and compared with former materials used in the exhaust manifold system such as low carbon steel A3 and 1Cr18Ni9 stainless. The results indicates that Fe₃Al based alloys and its weldment exhibited corrosion resistance to the test environment as good as stainless because of the producing of continuous and dense Al₂O₃ surface scale, by contrast, the oxide of A3 steel was loose and discontinuous Fe₂O₃ scale which was easy to be peeled off and led corrosion accelerated.