The present invention relates to a method for preparing nano noble metal hydrogenation catalyst by using chemical displacement process and its application. It is characterized by that it utilizes metal elementary substance M and salt of noble metal N and makes them undergo the process of displacement reaction to produce elementary substance N, in which the N represents Ru, Rh, Pd, Pt and Ir or their mixture, M represents Zn, Al, Fe, Co and Ni. When the M is terrifically excess, N/M type metal loaded nano noble metal can be produced; and When the N and M are approximate to stoichiometry, the highly-dispersed nano N colloid can be formed, after the stabilizing agent is added, the load type N/S can be prepared, in which S represents C, Al2O3, SiO2, MgO, ZrO2 and CeO2. Said catalyst can be used for hydrogenation reaction of various compounds.