The invention discloses a diesel hydrogenation catalyst carrier and a preparation method thereof. The catalyst carrier is taken as a standard and comprises solid cellosilk of 5-20wt%, modifying aid of5-20wt% and the balance of alumina. The preparation method includes: mixing alumina, the modifying aid and the solid cellosilk, forming, and calcining to obtain the improved diesel hydrogenation catalyst carrier with through small-and-medium pores, wherein elements of the modifying aid are nonmetal elements or IVBth-class metal elements, and the modifying aid is calculated according to oxide. Thecarrier has the through small-and-medium pores, approachability of the inner surface of the carrier is improved by higher than 5%, in other words, utilization rate of the active center of a catalystis increased, medium mass transfer resistance is lowered, dispersion of active metal components in the carrier is improved, and miscellaneous ability of the catalyst is improved; surface acidity is modulated through the modifying aid, so that hydrogenation desulfurization performance, hydrogenation denitrification performance and aromatic hydrocarbon saturation performance of the diesel hydrogenation catalyst are improved.