An amorphous alloy catalyst for hydrogenation and its preparation method are disclosed herein. The catalyst essentially consists of nickel ranging between 60 and 98 wt %, iron ranging between 0 and 20 wt %, one doping metal element selected from the group consisting of chromium, cobalt, molybdenum, manganese and tungsten ranging between 0 and 20 wt %, and aluminum ranging between 0.5 and 30 wt % based on the weight of said catalyst, wherein the weight percentages of iron and the doping metal element component may not be zero at the same time; and just one broad diffusion peak appears at about 2 &thgr;=45±1° on the XRD patterns of the catalyst within 2 &thgr; range from 20 to 80°. The catalyst herein can be used in processes for hydrogenation of unsaturated compounds such as olefin, alkyne, aromatics, nitro, carbonyl groups, nitrile and soon, and for hydrorefining of caprolactam in particular.