A new aryltetrahydronaphthalene lignan,(+)-cycloolivil formaldehyde condensate(1),was isolated from the whole plants of Epimedium brevicornum(Berberidaceae).Its structure was elucidated on the basis of MS,1D and 2D NMR techniques. A new aryltetrahydronaphthalene lignan, (+) - cycloaliphatic formaldehyde condensate (1), was isolated from the whole plant of Epimedium brevicornum (Berberidaceae) .Its structure was elucidated on the basis of MS, 1D and 2D NMR techniques.