Abstract: The chemical constituents of the fruits of Forsythia suspensa (Thunb.) Vahl were investigated by using chromatographic techniques (silica gel, MCI, and sephadex LH-20 gel column chromatography, etc). Fourteen compounds were isolated from the 95% ethanol extract of F. suspensa, and their structures were identified by HR-ESI-MS, NMR, and calculated electronic circular dichroism (ECD) methods. The compounds included labdane diterpenes (1-6), clerodane diterpene (7), norlabdane diterpene (8), norclerodane diterpene (9), oleanane triterpenoid (10), ursane triterpenoids (11, 12), lupane triterpenoids (13, 14). Among them, compound 1 was a new compound and compounds 3-9, 11, and 12 were obtained from this plant for the first time. The inhibitory effect of these compounds on lipopolysaccharide-induced nitric oxide production in mouse macrophage RAW 264.7 cells also was evaluated. Unfortunately, none of these compounds exhibited significant inhibitory activity.