Lithium/sulfur battery is very attractive for rechargeable lithium battery due to its high theoretical specific capacity of 1675 mAh/g-sulfur , high theoretical energy density of 2600 Wh/kg, low cost, and environmental friendliness . Unfortunately, during the charge-discharge process, the lithium polysulfide dissolves into electrolyte, which causes the loss of sulfur active material. Therefore, Li/S battery has bad cyclic durability at room temperature. To overcome such problems, the polysulfide dissolution into electrolyte should be retarded or prohibited. So, in this study, in order to improve the cycle life of Li/S battery. nano-sized Al2O3 was added to sulfur cathode as a additive to adsorb soluble polysulfide within sulfur cathode.