Aim To find the original active compounds from three medicinal plants of Menispermaceae family in Qinling Montain,Shaanxi,China.Method Several kinds of isolation techniques such as liquid-liquid partition,column chromatography,thin layer chromatography and sephadex LH-20 gel chromatography are used to separate the compounds and all kinds of identification techniques such as mass,high resolution mass,1H-NMR,13C-NMR,all kinds of 2D-NMR,CD spectra and X-ray diffraction analysis are used to determine the structure of the isolated compounds; several enzymes linked immunosorbent assay are used to test the biological activities of some isolated compounds.Results 30 alkaloids were isolated and identified from Sinomenium acutum of which 8 are new compounds; nine alkaloids were isolated and identified from Menispermum dauricum of which 6 are new compounds; six alkaloids were isolated and identified from Stephania epigaea.Among all the identified alkaloids,six compounds show protective effects against hydrogen peroxide induced cell injury; eight compounds show weak or strong cytotoxicity activity； one compound shows neuroprotective effect against hydrogen peroxide and.β-amyloid25-35-induced oxidative injury.Conclusion These three plants of Menispermaceae family may be considered as the potential drugs for Alzheimer' s disease therapy and anticancer agents.