The essential oil from flowers of Mikania micrantha H.B.K were extracted and its chemical constituents were analyzed by GC/MS. Forty-two compounds were identified and the main compounds with high contents were beta-cubebene (12.95%), allo-aromadendrene (11.67%), beta-caryophyllene (9.17%), 1H-inden-1-one, 5-(1, 1-dimethylethyl)-2, 3-(6.23%), beta-himaohalene (4.56%), trans-alpha-bergamotene (4.09%), limonene (3.68%), beta-ocimene (2.53%).