To investigate the preventive and therapeutic effects of Danshen Decoction on gastric ulcer in experimental animal models. The model of water immersion restraint stress ulcer in mice, and the models of acetic acid impaired gastric ulcer and pyloric ligation gastric ulcer in rats were established. The total gastric acid, the activity of pepsin and the amount of gastric wall binding mucus were detected. Danshen Decoction reduced the acute gastric mucosal lesion. The effect of 5.0 or 10.0 g/kg group was obviously better than that of the normal saline control group (P<0.05 and P<0.01 respectively). Danshen Decoction accelerated the healing of ulcer induced by acetic acid significantly, and increased the content of gastric wall binding mucus (P<0.01); and it also inhibited the formation of gastric ulcer induced by pyloric ligation, while having no influence on the secretion of gastric acid and the activity of pepsin. Danshen Decoction has a significant anti-ulcerative effect, which may be related to improving the gastric mucosal defensive function.