NiMo/γ?Al₂O₃ catalyst was prepared by using γ?Al₂O₃ as the carrier and Ni as the active component,and Mo was introduced to improve the metal dispersion of Ni?based catalysts.The physical properties of the catalysts were characterized by means of BET,XRD,H₂?TPD,H₂?TPR,and transmission electron microscopy.The performance of the catalysts was evaluated by hydrogenation units,and the effect of metal dispersion of the catalysts on the catalytic activity was investigated.The results show that the introduction of Mo can effectively weaken the interaction between Ni and the carrier.The low?temperature reduction peak of the H₂?TPR profile significantly moves forward,and the peak intensity is enhanced.The specific surface area of the catalyst activity increases from 0.7 m²/g to 15.3~16.1 m²/g,and the metal dispersion increases from 0.80% to 18.59%,which indicates that the number of metal active centers on catalyst surfaces increases,and the metal dispersion on the catalyst surfaces improves. Under the same process condition,heavy petrol with catalytic cracking is processed,and the desulfurization rate of NiMo?based catalysts is increased by 15.7% compared with that of Ni?based catalysts.The saturation rate of olefin is increased by 4.9%,and the desulfurization selectivity is decreased by 3.4%.Therefore,the NiMo?based catalysts have positive desulfurization selectivity while ensuring a high desulfurization rate.