The novel catalyst Ni-Cu alloys supported on carbon nanotubes (CNTs) was prepared by reduction with formaldehyde and applied in steam reforming of methanol. With nitric acid and sulfuric acid to create defects on the surface of CNTs and using ethanol to improve the hydrophilicity of CNTs, the Ni-Cu alloys were anchored on the surface of CNTs by co-reduction of Ni- and Cu-precursors under the use of tetra-n-methylammonium hydroxide to reduce the aggregation of Ni-Cu particles. In contrast, Ni-Cu catalyst supported on activated carbon (Ni-Cu/C) was prepared as well, and the bimetal of Ni and Cu supported on CNTs (Ni/Cu/CNTs) was attained by successive reduction of first Cu-and then Ni-precursors. The catalysts were characterized with XRD, ED, FESEM, transmission electron microscopy, and Thermogravimetric analysis. The hydrogen yield in steam reforming of methanol was near 100% at 360 degrees C over 20 wt.% Ni-20-Cu-80/CNTs. The catalytic activity of Ni-20-Cu-80/CNTs is much higher than that of Ni-20-Cu-80/C and Ni-20/Cu-80/CNTs.