Objective The aim of this study was to investigate the effect of left-handed pantoprazole sodium on rat models of gastric ulcer generated by pyloric ligation. Methods The rat models induced by pylorus ligation were treated with a single intravenous injection of left-handed pantoprazole sodium. The gastric ulcer inhibition rate, volume of gastric juice, activity of pepsin, and level of serum gastrin were determined and gastric mucosa tissue was examined by pathology. Results The gastric ulcer index, volume of gastric juice, activity of pepsin and level of serum gastrin in the rats pretreated with left-handed pantoprazole sodium (0.9, 1.8, 3.6 mg/kg, i.v.) were significantly lower than those in the model group. The lesions of gastric mucosa were also improved in the pantoprazole-treated groups. Conclusions Left-handed pantoprazole sodium has remarkable protective effects on the gastric mucosa in rat models of gastric ulcer induced by pyloric ligation.