Superoxide dismutase( SOD)is an important antioxidant enzyme,and plays an important role in active oxygen metabolism to regulate the balance between oxidation and anti-oxidation. Helicobacter pylori( Hp)infection,one of the risk factors of gastric cancer,can induce large number of reactive oxygen species by chronic inflammation,which causes DNA damage and high risk of gastric cancer. Expression of SOD is correlated with risk,metastasis and prognosis of gastric cancer. Studies on SOD can provide great help for the prevention and treatment of gastric cancer.