Abstract: Physiological and biochemical approaches were used to study engenol-induced resistance of tobacco plant against tobacco mosaic virus (TMV).Pretreatment with eugenol before TMV inoculation enhanced the accumulation of chlorophyll and the transcript abundance of PR-1, PR-3, PR-5 in tobacco.Eugenol-induced decrease in the concentration of MDA might result from the increase of the activities of antioxidative enzymes,such as peroxidase (POD) and superoxide dismutase (SOD).Pretreatment with eugenol also induced the increase of the activity of phenylalanine ammonium lyase (PAL),which plays important role in protecting plant from virus attack.These results suggested that eugenol might attenuate the harmful effects of TMV on tobacco plant by modulating plant defense system.