Abstract: The desulfurizers Mo and/or Ni-Mo supported on the phenolic resin-based activated carbon were prepared with water-soluble phenolic resin and metal salts as the precursors by a series of procedures including the reduced pressure distillation, solidification, carbonization, activation and presulfuration. The hydrodesulfurization of carbonyl sulfide (COS) on the as-prepared desulfurizers MS_x-AC was investigated under different operation conditions (the metal used and its loading, reaction temperature, reaction time and COS feed concentration). The results showed that the water-soluble phenolic resin is an appropriate precursor for the preparation of AC supported catalysts for COS hydrodesulfurization. The catalytic activity of bimetal Ni-Mo/AC desulfurizer is higher than that of mono-metal Mo/AC. The hydro-conversion of COS on the MS_x-AC desulfurizers is an internal diffusion control process, and a certain level of sulfur species in the reaction system is necessary to prohibit the presulfided desulfurizers from sulfur loss and then to maintain their catalytic activity.