The CeO2 nano-crystal less than 10 nm was fabricated by using thermal decomposition method with Ce(OH)(4) as the raw material. CeO2 nano-crystal with abundant -OH and -NO2 was used as the additive in the sulfur cathode. The additive can adsorb sulfur and lithium polysulfides during charge/discharge process, suppressing the dissloving and migrating of lithium polysulfides in the electrolyte. Thus the "shuttle effect" caused by dissloving of lithium polysulfides can be evidently inhibited, resulting in the enhanced cycle performance and the improved coulombic efficiency of Li-S battery. Furthermore, CeO2 nano-crystal with abundant -OH and -NO2 is beneficial to enhance the wettability between electrolyte and sulfur cathode, improving the utilization rate of active material. With 5wt% CeO2 nano-crystal added in the sulfur cathode, the discharge capacities at 0.1C and 0.5C (1C=1675 mA/g) after 100 cycles are as high as 750 mAh/g and 598 mAh/g, respectively, both much higher than those of the sulfur cathode without CeO2 nanocrystal. Simultaneously, the resistance of the cell is also reduced evidently before and after cycling owing to the addition of CeO2 nano-crystal in the cathode.