Objective To investigate the effects of Xanthoceraside on the learning and memory impairment induced in mire by innacere-broventricular injection of aggregated amyloid β peptide _(1-42)(Aβ_(1-42)). Methods Learning and memory functions in mice were examined us-ing step-through test and water maze test. Biochemical determination of acetylcholinesterase (AchE) and choline acetyl transferase (ChAT) were measured with spectrophotometric melhod. Results Administration of Xanthoceraside reduced number of error and prolonged the laten-cy in step-through test in mice impaired by Aβ_(1-42) (P < 0.05,P< 0.01,respectively). In water maze test,the swimming time decreased in mice treated with Xanthoceraside compared with the model mice impaired by Aβ_(1-42) (P< 0.05,P< 0.01,respectively). The results of bio-chemical determination showed that decrease level of AchE and ChAT in mice impaired by Aβ_(1-42) were significantly ameliorated by Xantho-ceraside administration (P < 0.05 and P < 0.01). Conclusion Xanthoceraside has the effect of improving learning and memory impairment in mice inducel by intracerebroventricular injection of Aβ_(1-42) via enhancing the cholinergic system functions.