Abstract: The secondary metabolites of the endophytic fungus Aspergillus fumigatus derived from Euphorbia royleana was studied. Silica gel column chromatography, Sephadex LH-20 gel and liquid chromatography were used to separate and purify of Aspergillus fumigatus. The compounds were identified according to their physical and chemical properties and spectroscopic data. Three compounds ( 1 — 3 ) were isolated from the endophytic fungus A. fumigatus. Their structures were identified as methyl 4-(3,4-dihydroxyphenyl)-2-hydroxy-4-oxobutanoate ( 1 ), arctiin ( 2 ) and 3-hydroxy-4-methoxy-phenylethanol ( 3 ). Compound 1 is a new phenolic component named as methyl 4-(3,4-dihydroxyphenyl)-2-hydroxy-4-oxobutanoate ( 1 ).