Abstract: Essential oils（EOs） are rich in a variety of antibacterial ingredients and have the good potential in the development of natural antimicrobial agents. In the present study, the 2-fold dilution method was used to investigate the in vitro antibacterial activities of clove, lavender, eucalyptus leaves, citronella, and nutmeg essential oils,and the minimum inhibitory concentrations（MICs） of these essential oils against gram-negative bacteria and grampositive bacteria were quantitatively measured by suspension culture. Furthermore, the components and relative contents of essential oils were analyzed by gas chromatography-mass spectrometry（GC-MS）. Results showed that the MICs of clove essential oil（CLEO）, lavender essential oil（LEO）, eucalyptus leaves essential oil（EEO）, citronella essential oil（CEO）, and nutmeg essential oil（ NEO） against Escherichia coli were 1.25 μg/m L, 5.00 μg/m L,10.00 μg/mL, 10.00 μg/mL, and 5.00 μg/mL, respectively. Corresponding MICs against Bacillus subtilis were0.63 μg/mL, 1.25 μg/mL, 2.50 μg/mL, 1.25 μg/mL, and 0.31 μg/mL, respectively. GC-MS analysis demonstrated that the main components of CLEO were eugenol（84.90%） and caryophyllene（13.27%）; the main components of LEO were linalyl acetate（34.05%） and linalyl acetate（28.40%）; the main components of EEO were eucalyptol（34.29%） and limonene（18.29%）; the main components of CEO were citronellal（16.22%） and cuparene（16.04%）;the main components of NEO were limonene（32.68%） and pinene（23.96%）. Five EOs all presented good antibacterial activities, which could provide theoretical basis for better development of alternatives to antibiotics.