Abstract: The chemical composition of essential oil in Caryopteris terniflora, which was collected by steam distillation-solvent extraction, has beenstudied by GS-MS technique. More than fifty substances have been seper-ated, among which twenty five compounds were identified. The peak areaof identified substances is 63.78% in total chromatographic area. Theamount of the oil contained in the plant is 1.003%. It was proved thatmain compounds occured in the volatile oil belong to terpenoid such aslimonene (37.40%), α-pinene and so on. The chemical composition of theessential oil in this plant has not been reported previously.

Key words: Caryopteris terniflora, Essential oil, Chemical components, Gaschromatography, Mass saectrometry