The invention provides a method for preparing a non-supported hydrogenation catalyst, wherein the method comprises the steps of allowing a solution of at least one VIII-group non-noble metal compound to be in contact with a solution of at least one VIB-group metal compound, obtaining slurry and then subjecting the slurry to hydrothermal treatment. The non-supported hydrogenation catalyst preparedby the method has larger specific surface area and pore volume and smaller in particles, thereby having higher hydrogenation activity. In addition, as no sulfide unbeneficial to environment is introduced during the preparation of the catalyst, the method has the advantages of mild reaction conditions, simple stable operation, low requirements on equipment and low cost.