Fucinum A (1),a novel peroxy bond-containing dimeric benzene derivative,together with six known compounds (Z)-1-hydroxy-4-(2-nitroethenyl)benzene (2),p-hydroxybenzaldehyde (3),stigmasta-4,6,8(14)-trien-3-one (4),stigmast-4-ene-3,6-dione (5),ergosterol (6),5-hydroxymethyl furfural (7) were firstly isolated from plant endophytic fungus Fusarium guttiforme based on the comprehensive chromatographic methods.Their structures were elucidated on the basis of spectroscopic analyses,including HR-ESI-MS,1D and 2D NMR experiments.Additionally,all of them were evaluated on the NO production inhibition activity.The results showed that compounds 1 and 2 exhibited inhibitory effects against NO production with IC₅₀ values of 48.1 and 46.6 μmol/L,respectively.