Jasmonic acid(JA) is closely related to plant disease resistance and insect resistance.In order to select aphid resistant tobacco varieties and study its mechanism,leaf test in vitro and pot experiment were used to identify the aphid resistance of 12 tobacco varieties,and the changes of JA content before and after aphids infestation were analyzed.The results showed that four tobacco varieties,such as Qieke,Tailifei 2411, Shubalaomuji 2113 and Wangpoer showed resistance to aphid; the aphid resistance of Wuchuanheiyan,Hongxianxiangdayeyan, MC Nair and Vesta 33 were moderate; Zhongyan 100 and SpeightG-28 were susceptible to aphid; the Luositou 2474 and Yunyan 97 showed high sensitivity to aphid.The content of endogenous JA in aphid resistant tobacco varieties was significantly higher than that in other varieties.The content of JA increased significantly in 12 tobacco varieties after aphid infestation.The increase amount and increase range of JA in aphid resistant tobacco varieties were greater than those in aphid susceptible tobacco varieties.JA content had a good correlation with aphid resistance,which could be used as a physiological index for identification of aphid resistance in tobacco varieties.