1 gastric ulcer and helicobacter pylori infection have close relations, and helicobacter pylori infection can make gastric mucosa in inflammation and damage state, weaken the local defense function, so easy to ulcer. 2. Gastric ulcer have certain genetic, especially the men had family history of gastric ulcer, the children who suffer from the disease were more than no family history, this and helicobacter pylori spread to run in the family has a certain relationship. In addition the person of O blood with the risk of gastric ulcer, because blood contains anti secretory type IgA antibodies. 3. Gastric acid and pepsin own digestive function, pepsin role is to analyze protein molecules, so for the mucosa has hit role, and pepsin is gastric acid activation pepsinogen, so in the pathogenesis of gastric acid process play an important role.