Essential oil was extracted from Artemisia lavandulaefolia DC. by steam distillation(SD) and supercritical-CO2 fluid extraction(SFE), respectively. The constituents of the essentil oils extracted with those two methods were analyzed by gas chromatography-mass spectrometry(GC-MS) and insecticidal activities of the essential oils were evaluated, then the results were compared to assess their biological activity. Thirty-one compounds were identified in the essential oil extracted by SD, and its main components were eucalyptol, α,α,4-trimethyl-3-cyclohexene- 1-methanol and so on. Twenty-two compounds were identified for the essential oil extracted by SFE, and its main components were cyclodecene, n-hexadecanoic acid and so on. Six chemical compositions were all contained in the essential oils extracted by the two methods, i.e., eucalyptol, α,α,4-trimethyl-3-cyclohexene-1-methanol, caryophyllene, [3aS-(3aα,3bβ,4β,7α,7aS)]-octahydro-7-methyl-3-methylene-4-(1-methylethyl)-1H-cyclopenta[1,3]cyclopropa- [1,2]benzene, nerolidol and (-)-Spathulenol. The fumigation toxicity of the essential oil obtained by means of SD to the adults of Sitophilus zeamais is significantly higher than that of the essential oil by means of SFE. The contact toxicity of the essential oil obtained by means of SFE to the adults of S. zeamais is higher than that of the essential oil obtained by means of SD, but the difference is not significant.