CeO2 promoted palladium catalysts supported on Al2O3 were prepared using the impregnation (IM) and the deposition-precipitation (I)P) methods. The activities and sulfur tolerance of the catalysts for hydrodesulfurization (HDS) were detected with thiophene HDS as probe reaction. H-2 adsorption, XRD, FTIR, NH3-TPD, XPS were used to characterize the catalysts. The Pd-CeO2/Al2O3 (IM) catalyst was highly active for the HDS reaction, and it had much stronger sulfur tolerance than the Pd/Al2O3 catalyst. Pd-CeO2/Al2O3 (DP) showed excellent sulfur tolerance while its initial activity decreased. It was observed that with the chlorine bridge, the interfacial structure of Pd-Cl-1-Ce3+ was responsible for the high activity of the Pd-CeO2/Al2O3 (IM) catalyst, at the same time the interaction of Pd with Ce was weakened by Cl1-ions. The enhanced sulfur tolerance over the Pd-CeO2/Al2O3 (IM) catalyst was attributed to the weakened Pd-S bond caused by the competitive adsorption of H2S on Ce3+ ions. As to the Pd-CeO2/Al2O3 (DP) catalyst, a strong interaction of Pd with Cc put Pd at an electron-deficient state, the creation of sulfided palladium was therefore inhibited.