Abstract: A new compound named lactiflorasyne has been isolated from the flowers and leaves of Artemisia lactiflora Wall. The molecular formula of lactiflorasyne was proved to be C₁₉H₂₂O₅ by high resolution measurements. Lactiflorasyne contains an ester group, a spiro system and two triple bounds. On the basis of spectroscopic analysis (UV, IR, MS, NMR)and X-ray crystallographic study structure Ⅰ was finally established for lactiflorasyne.