Abstract:The lemongrass essential oil （LEO）extracted from the leaves of lemongrass in Southwest China was obtained by steam distillation.The composition and relative content of LEO were analyzed by gas chromatography-mass spectrometry （GC-MS）.The effect of antibacterial activity of LEO against Escherichia coli，Staphylococcus aureus，Bacillus subtilis were studied by bacteriostatic circle method and the minimum inhibitory concentration method.To studied the preservation effect of LEO with various treatments of LEO concentration on the quality and physiology of freshly picked Kyoho grape products.The results showed that maximum yield of 0.91 % at a ratio of 1 ∶15 （g/mL）.Using GC-MS to analyzied the components of LEO，of which there were 21 components and the main component was citral，accounting for 70.11 %.LEO had great antibacterial effects.The inhibitory zone diameters of LEO against B.subtilis，S.aureus and E.coli were 23.8，22.5 mm and 11.2 mm，respectively.Minimum inhibitory concentration of LEO against E.coli，S.aureus and B.subtilis were 0.2，0.1 μL/mL and 0.1 μL/mL，respectively.It indicated that LEO against bacteria with S.aureus and B.subtilis had higher activity than E.coli.In addition，compared with the control group，the treatment of LEO effectively alleviated the decrease of titratable acid，soluble solid content and hardness，reduced the rate of rotten fruit and weight loss rate and the preservation effect of 0.50%lemongrass essential oil treatment group was better than other treatment groups obviously.These findings clearly indicated that effects of antibacterial activities and fruit preservation of LEO were observed.