Helicobacter pylori(Hp) causes gastritis and peptic ulcer disease of a human being, and is associated with certain types of gastric cancer. In recent years, much attention has been focuced on its moclecular mechanisms of H.pylori infection. As an important human pathogen, Hp genome has been sequenced. A detail summary of the literature, significant genome structure feature, gene expression regulation, and indentificaton of virulence factors is provided.