Abstract: To make clear the allelopathic effects of Allium Sativum L.on flue-cured tobacco cv.K326,Yunyan 85,Zhongyan 100,NC89,CB-1 and F1-35,the volatile and extract of garlic and soil(0-10 cm),which planted garlic before,were used to assess their effects on tobacco seed germination,seedling growth and adult seedling growth.The results indicated that garlic had allelopathic effects on the tested tobacco.The inhibitory rates of fresh garlic volatile to the accumulation of fresh organic matter in different flue-cured tobacco seedlings ranged from 33.91% to 57.89%.The ethanol-soluble extracts of garlic had strong inhibiting effects on seed germination,its inhibitory rates ranged from 7.00% to 100.00%.And the accumulation of fresh organic matter in different flue-cured tobacco seedlings were also inhibited by the soil,its inhibitory rates ranged from 8.35% to 60.96%.However,the growth of adult seedlings was not significantly inhibited by garlic extracts or the soil.It indicated that the negative allelopathy is negligible when garlic is used as a rotate crop in flue-cured tobacco production.