The decomposition of nitric oxide was studied over carbon nanotubes supported metals catalysts.The carbon nanotubes were synthesized by means of CO disproportionation over Ni-based catalysts.At 600℃, the carbon nanotubes yield was 100g/gNi in 10 hours reaction.Carbon nanotubes supported iron, copper and manganese catalysts were tested as catalyst for NO decomposition.For 5wt % metal loaded CNTs catalysts, the NO decomposition activities declined in the order of Fe/CNTs>Mn/CNTs>Cu/CNTs.When reaction temperature was at 500℃, the NO decomposition conversion reached 80%, 68%, and 60% over Fe/CNTs, Mn/CNTs, Cu/CNTs,respectively.The catalytic mechanism was studied extensively by use of the techniques of Temperature Programmed Desorption (TPD), XRD, Insitu FTIR, Raman, XPS, SEM, TEM, etc.TEM investigation revealed that the iron particles distributed rather evenly over CNTs with a particle diameter around 8 nm.XRD results indicated that there was interaction between the carbon nanotubes and loaded metals.XPS investigation demonstrated that the reduced state of metal was responsible for the high NO decomposition.The NO decomposition gone through a Redox mechanism with the N2O2 as the key intermediate.The surface oxygen species on the catalyst participated in the catalytic process.The influence of reaction temperature on the NO decomposition activity was studied as well and the results revealed that at the temperature below 400℃, the product NO2 was easily formed while above 600℃, the major products were N2 and O2.