Unsupported Nd-Ni catalysts were prepared and their catalytic behaviors for thiophene hydrodesulfurization(HDS) were investigated. A series of Nd-Ni catalysts were prepared by precipitation method and characterized by temperature programmed desorption(TPD), X-ray diffraction(XRD) and scanning electron microscopy(SEM). Effects of atomic ratio of Nd to Ni, hydrogen partial pressure, calcination and presulfiding temperature on the catelytic activities of Nd-Ni catalysts for thiophene HDS were investigated and compared with those of conventional Ni-Mo/$Al_2O_3$ catalysts. Nd-Ni catalysts showed synergistic activity for thiophene HDS, although their activities were lower than those of conventional NiMo/$Al_2O_3$ catalysts. The thiophene HDS activities of uncalcined Nd-Ni catalysts were higher than those of calcined catalysts and showed maximum value when the catalysts were presulfided at 350℃. Nd-Ni catalysts had higher resistance to poisoning by $H_2S$ than conventional NiMo/$Al_2O_3$ catalyst, which was tested by varying flow rate of $H_2S$/$H_2$ during the reaction at 475℃. It was found that thiophene HDS activities of Nd-Ni catalysts were less affected by hydrogen partial pressure than those of conventional NiMo/$Al_2O_3$ catalysts. The XRD and SEM measurements showed that uncalcined $NdNi_5$ catalyst with the highest thiophene HDS activity had the lowest crystallinity and lower sintering rate.