Precipitated alumina(or silica-alumina) was mixed with zeolite Y(or mordenite), and then cobalt and molybdenum oxide were impregnated on these substrates. These prepared catalysts and commercial desulfurization catalysts were characterized by measuring specific surface area, pore volume and average pore diameter, and examined for the hydrocracking of vacuum gas oil in a batch reactor. The catalysts mixed with silica-alumina have larger mesopore size and smaller surface area than those mixed with alumina. The former showed higher activity and smaller coke amount than that of the latter. The conversion of VGO was increased with the Y content in substrate up to 33 wt%, and then decreased due to probable decrease of cracking rate on substrate. It was suggested that benzene, toluene and xylene(BTX) were formed from n-paraffin produced via VGO cracking on the substrate because they were increased with Y content. The boiling point distribution of the product on zeolite/alumina was smaller than that on zeolite/silica-alumina