Abstract: The volatile oils of different parts of Microtoena insuavis (Hance) Prain ex Dunn were extracted by headspace solid-phase micro-extraction (HS-SPME) method. Their chemical composition was qualitatively analyzed by GC-MS based on Kovats retention indices and was quantified by peak area normalization method. Totally 74 volatile constituents in the stems ,105 in the leaves and 85 in the flowers of M. insuavis (Hance) Prain ex Dunn were separated and identified, accounting for 97.34%, 98.80% and 97.96% of the total peak area, respectively. The main components in the stems were neryl acetate (5.63%), β-caryophyllene (17.32%), α-bergamotoilene (7.56%), trans-β-farnesene (10.2%) and caryophyllene oxide (5.21%), and in the leaves Z-citral (11.64%), geranial (16.35%), neryl acetate (8.44%), β-caryophyllene (13.08%), trans-β-farnesene (10.88 %) and caryophyllene oxide (8.34%), and in the flowers Z-citral (21.49%), geranial (27.5%), neryl acetate (9.99%), β-caryophyllene (5.47%) and trans-β-farnesene (10.11%). It was also observed that there were significant differences in the relative contents of chemical components in the three parts of M. insuavis (Hance) Prain ex Dunn.

Key words: Microtoena insuavis (Hance) Prain ex Dunn, volatile oils, headspace solid-phase micro-extraction (HS-SPME), gas chromatography-mass spectrometer (GC-MS)