The invention discloses a volume-phase hydrogenation catalyst and a preparation method thereof. The catalyst is spherical particles, and pore diameter distribution has the following characters: an average pore diameter d1 from a center of the catalyst particle to x*R is 50-100 nm, wherein x is 0.1-0.9, an average pore diameter d2 from the catalyst particle x*R to the outer surface of the catalystis 120-180 nm, and d2-d1=40-130 nm. The volume-phase hydrogenation catalyst has the following characters: a specific surface area is 200-300 m<2>/g, a pore volume is 0.7-0.9 mlg-1, and an average porediameter is 30-120 nm, wherein pore distribution less than 30 nm accounts for 5%-10% of a total pore volume, 30-100 nm of the pore distribution accounts for 50%-60% of the total pore volume, the poredistribution greater than 100 nm accounts for 30%-40% of the total pore volume. The volume-phase hydrogenation catalyst is larger in pore volume and pore diameter, and the pore diameter of the outersurface is greater than the pore diameter of the interior. Surface-phase reactive metal density of the catalyst is larger, a utilization ratio of a hydrogenation reactive metal and a utilization ratioof the interior of the catalyst are higher, a catalyst deactivation rate is reduced, and service life of the catalyst is improved. The method is capable of realizing continuous production of the hydrogenation catalyst, improving production efficiency, and reducing production cost.