Objective To investigate the gastric protective effect of Albizia chinensis extract on acute gastric ulcer model in rats and its mechanism related to H+,K+-ATPase in gastric parietal cells. Methods Rats were injected intraperitoneally with indo?metacin or kept under water immersion-restraint stress(WRS)to establish acute gastric ulcer model. Test samples were orally given 30 min before induction of gastric ulcer,and the gastric ulcer index and inhibitory rate were used to evaluate the effect of A. chinensis extract. Gastric mucosa pathological tissues in rats were observed by HE staining,the enzymatic activity of proton pump on isolated gastric parietal cells was measured,and the translocation of gastric proton pump was observed by immunofluorescence cell staining. Results The A. chinensis extract inhibited the gastric ulcer with the inhibition rate of 70.0%and 75.4%at 300 mg/kg in the WRS and indomethacin-induced rat model,respectively. The extract could also inhibit the enzymatic activity of gastric proton pump with the in?hibition rate of 21.5%,29.4%,44.1%,51.9%,57.7%and 62.9%(P<0.01)at 15,30,60,120 and 480 mg/L,respectively. The half-effective dosage(ID50)of the extract was determined to be 130 mg/L. The extract showed no significant effect on the translocation of gastric proton pump. Conclusion The A. chinensis extract(300 mg/kg,ig)could significantly prevent the formation of gastric ul?cer in rats via inhibiting the enzymatic activity of gastric proton pump.