The measurement of thiopbene hydrodesulfurization (HDS) and pyridine hydrodenitrogenation activities is carried out in a fixed--bed reactor at a hydrogen pressure 3. 0MPa. The results show that the catalitic activity and stability of sulfided CoMo/(TiO_2-Al_2O_3) are superiored to molybdenum nitride on the reaction of thiophene hydrodesulfurization, but the HDN activity of Mo_2N is obviously higher than that of sulfided CoMo/(TiO_2-Al_2O_3). The disadvantage of Mo_2N on thiophene hydrodesulfurization is due to the blockage of small pores in Mo_2N particles by less dense MoS_2, whereas the superiority of Mo_2N on hydrodenitrogenation results from the adsorbsive behavior of pyridine on the surface of Mo_2N.