Two kinds of volatile oil were extracted by steam distillation extraction (SDE) and supercritical fluid extraction of CO2 (SFE-CO2), and then they were identified by gas chromatography-mass spectrometry (GC—MS). The antimicroble effects of the extract on different rot funguses in fresh milk was evaluated in 4 ℃ within 10 days. There were 39 different components in the two kinds of volatile oil, including methyl cyclohexane, octacosane, 1,3-dimethyl-benzene, and dibutyl phthalate mainly found in the SDE volatile oil, and 4-(4-ethylcyclohexyl)-1-pentyl-cyclohexene, toluene, 1,2-benzenedicar-boxylic acid, diisooctyl ester, 1-ethoxy-pentane, 2-methoxy-4-vinylphenol, and 2,4-bis(1,1-dimethylethyl)-phenol mostly presented in the SFE-CO2 volatile oil. The differences among the contents of 20 common components in two oils was great. The SFE-CO2 volatile oil showed more effective antimicrobial activity with the MIC range of 0.031～0.125 mg/mL. Moreover, those from SFE-CO2 volatile oil coulld also provide better exotic perfume and stronger antiseptic functions.