Eupatoriurn odoratumaerial parts were extracted with ligarine and the volatile constituents isolated were analyzed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). Volatile constituents were isolated from the ground aerial parts ofE. odoratumby ligarine extraction and analyzed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). As a result, a total of fifteen compounds represented all of the extract were identified, amongst nine of fifteen compounds were sesquiterpenes. Esters and sesquiterpenes were found to compose three major chemotype accounted for 58.58% and 30.80% of the constituents, respectively. The main components was demonstrated to be dibutyl phthalate (39.73%), 11,14,17-eicosatrienoic acid, methyl ester (13.20%), (S)-spiro [4.nona-1,6-diene (6.80%), 1,2-benzenedicarboxylic acid, bis (2-methylpropyl) ester (5.65%) andcis-Z-α-bisabolene epoxide (5.56%). In addition, some pharmaceutical components such as α-cadinol and germacrene D were discovered. Antioxidant activity of the extract was assessed by the free radical scavenging (DPPH). The study offers theoretic basis for pharmaceutical utilization of the medicinal plantE. odoratum.