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℃).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.