An evidence for the synergetic effect between the stacked bed of Mo/γ-Al2O3 and Ni/γ-Al2O3 in the hydrodenitrogenation (HDN) reaction of quinoline has been provided in this paper. The synergism factor decreases when the reaction temperature increases (280?340 ?C). The synergetic effect leads to improve the hydrogenation activity for the stacked bed compared with the single Mo/γ-Al2O3 bed, which may be attributed to the generation of hydrogen spillover on the Ni/γ-Al2O3 catalyst. An evidence for the synergetic effect between the stacked bed of Mo / γ-Al2O3 and Ni / γ-Al2O3 in the hydrodenitrogenation (HDN) reaction of quinoline has been provided in this paper. The synergism factor decreases when the reaction temperature increases (280? 340? C). The synergetic effect leads to improve the hydrogenation activity for the stacked bed compared with the single Mo / γ-Al2O3 bed, which may be attributed to the generation of hydrogen spillover on the Ni / γ-Al2O3 catalyst.