The amorphous NiB/SiO2 catalyst, prepared by reductive-impregnation method, showed higher sulfur resistance than the amorphous NiP/SiO2, the crystallized NiB/SiO2 and Ni/SiO2 catalysts when poisoned by carbon disulfide in the partial hydrogenation of cyclopentadiene to cyclopentene. The hydrogenation was carried out in a fixed-bed reactor at atmospheric pressure. When the sulfur (CS2) concentration was about 10 ppm, no significant deactivation of the amorphous NiB/SiO2-catalyst was observed during 1000 h of hydrogenation, while the other catalysts were obviously deactivated in 24 h under similar reaction conditions. The higher sulfur (CS2) resistance that the amorphous NiB/SiO2 catalyst showed could be explained on the basis that CS2 was reversibly absorbed on the boron prior to nickel at low S concentration. XPS characterization revealed that boron donated electrons to the alloying nickel, which might make nickel adsorb sulfur less easily.