Abstract:Known diterpenoid maoyerabdosin was isolated from the leaves of Rabdosia macrocalysc (Dunn) Hara. Based on elemental analyses and spectra of MS, NMR, COSY and NOESY, the structure of maoyerabdosin was revised as ent-7β-20-epoxy-lα, 7α, 15α, 16α-tetrahydro- xy kaurene-6α, 17-diacetate.