Abstract: In order to study the chemical composition of Osmanthus fragrans var. thunbergii, the chemical constituents of the dried flower of O. fragrans var. thunbergii were studied. From the 95% ethanol extract of the dried flower, a new monoterpene (1), along with seven known monoterpenes, sesquiterpenes and phenethyl alcohols (2-8), was isolated and purified by silica gel, polyamide, and preparative reversed-phase HPLC chromatography methods. Their structures were identified by 1D-NMR (¹H NMR, ¹³C NMR, DEPT), 2D-NMR (HSQC, HMBC, ¹H-¹H COSY, NOESY), HR-ESI-MS, IR, UV, and its physical and chemical properties as:methyl (R,E)-2-(5-ethylidene-2-oxotetrahydro-2H-pyran-4-yl) acrylate (1), (R,E)-2,6-dimethyloct-3,7-dien-2,6-diol (2), (6R)-2,6-dimethyloct-7-en-2,3,6-triol (3), 2,4,4-trimethyl-3-(3-oxobutyl)-cyclohex-2-en-1-one (4), (S)-2,4,4-trimethyl-3-(3-hydroxybutyl)-cyclohex-2-en-1-one (5), (R,E)-2,4,4-trimethyl-3-(3-hydroxybut-1-en-1-yl)-cyclohex-2-en-1-one (6), (S,E)-3,5,5-trimethyl-4-hydroxy-4-(3-oxobut-1-en-1-yl)-cyclohex-2-en-1-one (7), and 2-p-acetoxyphenylethanol (8). 1 is a new compound, 2-8 were isolated from the plant of Osmanthus fragrans var. thunbergii for the first time.