The invention discloses a hydrogenation catalyst, its preparation method and application in maleic acid dialkyl ester and/or succinic acid dialkyl ester hydrogenation to prepare 1, 4-butanediol. The catalyst is a Cu-Al-A-B-O catalyst, wherein A is one or more of Zn, Mo and W, and B is one or more of Ba, Mn, Mg, Ti, Ce and Zr. According to the method provided in the invention, part of Cu, A, and the remaining Cu, Al and B are subjected to parallel flow precipitation in two steps under different conditions, and the second step of precipitation for the remaining Cu, Al and B is carried out based on the first step precipitation, thus being in favor of forming a stable skeleton structure difficult to collapse during reaction in the catalyst. Also, the catalyst can have an appropriate acid content and acid distribution, and the reaction activity, selectivity and stability of the catalyst are improved.