Abstract: Essential oils were isolated from the leaves and flowers of Rosmarinus officinalis Linn. respectively in this experiment. The oils were analyzed by gas chromatography coupled to mass spectroscopy(GC/MS) in order to determine their chemical compositions and contents. We have found 30 compounds in the oils and identified 20 compounds of them. The results of analysis showed that the contents of low boiling point components such as α-pinene, camphene, β-pinene, α-phellandrene and β-myrcene in flower oil, which are 17.58%、13.19%、1.13%、2.03% and 1.02% respectively, are lower than those in leaf oil. And the contents of high boiling point components such as camphor, borneol and bornyl acetate in flower oil which are 11.97%、8.48% and 4.29% respectively, are higher than those in leaf oil.

Key words: Rosmarinus officinalis Linn., leaf oils, flower oils, GC-MS