Abstract: Objective:To determine the optimum extraction conditions of polyphenols from sea buckthorn(Hippophae rhamnoides L.)fruit(SBP)and preliminarily evaluate its anti-alzheimer's disease activity. Methods:On the basis of single factor experiments,the optimum extraction conditions of SBP were investigated by central composite design-response surface(CCD-RSM). 60 mice were randomly divided into control group,positive group model group and high-dose,medium-dose,low-dose group of SBP. AD model was induced by D-galactose combined with aluminum chloride. The escape incubation period of mice were recorded learning. Exploration incubation period and the times of exploration were recorded after last administration. ELISA was used to determine the content of acetylcholine(Ach),acetylcholine esterase(AChE)and choline acetyltransferase(ChAT)in mice brain and observation of hippocampal neuronal damage in mice brain by hematoxylin-eosin staining. Results:The optimal extraction conditions were as follows:71% ethanol as extraction solvent,a liquid/solid radio of 20:1 mL/g and an extraction time of 32 min. Under these optimized conditions,the extraction yield of polyphenols was 3.0813 mg/g. Compared with the model group,the escape incubation period was shortened extremly significant(P<0.01),exploration latency was prolonged and the number of explorations was decreased in Morris water maze experiment significantly(P<0.05),the morphological changes in hippocampal region was improved and significantly increased content of Ach content extremly significant(P<0.01),extremly significant decreased content of AchE content(P<0.01),and significantly increased content of ChAT content(P<0.05)in the high-dose group of SBP. Conclusion:Using central composite design-response surface to optimize SBP alcohol extraction process,the actual and predicted values are consistent with high and good predictability which is feasible. The SBP have good anti-Alzheimer's disease activity.