Abstract:A novel diterpene bisepoxide, ,riptriolide was isolated from the root and leaves of Tripterygium wilfordii Hook- f. Triptriolide was obtained as white cluster crystal, mp. 260-262℃. Its molecular formula is C20H26O7. The structure and stereochemistry of triptriolide were determined by UV, IR, MS, 1H-NMR, 13C-NMR, 2d-NMR, 13C-NOE, NOE difference spectroscopy and direct X-ray crystallographic analysis. Preliminary pharmacologic assay revealed that triptriolide has a potent anti-inflammatory action.