Abstract: We have studied the flower buds of Tussilago farfara L. collected from Yulin county Shaanxi Province and have isolated a new terpenoid compound Ⅰ with the composition C₂₃H₃₄O₅, M⁺ 390.2416, mp 100～101℃. On basis of physical and chemical propertes and spectroscopic analysis (UV, IR, ¹HNMR, ¹³CNMR, ¹H-¹H-COSY, ¹³C-¹H-COSY DEPT, EI-MS, FAB-MS, HR-MS) and X-ray, the Structure of Ⅰ has been elucidated as a novel sesqui terpenoid compound, which is named farfaratin.