Abstract: Helicobacter pylori infection is one of the most common chronic infections in humans. At present,the rate of H. pylori infection in Chinese population ranges from 40% to 50%. The persons infected with H. pylori almost all have chronic active gastritis. Peptic ulcers and dyspepsia might develop in some infected persons,and gastric cancer might develop in small number of the infected persons. Therefore,H. pylori infection is a major cause of stomach diseases. In addition,H. pylori infection is also closely related to the pathogenesis of some extragastric diseases,such as unexplained iron deficiency anemia and idiopathic thrombocytopenic purpura. The eradication of H. pylori plays an important role in the treatment and prevention of the related diseases. H. pylori infection can be transmitted from person to person through oral- oral,fecal- oral and stomach- oral routes;H. pylori is mainly transmitted in families. Promoting healthy habits can facilitate the reduction of H. pylori transmission.