Abstract:Ethanol extract from Atractylodes lancea rhizome was ultrasonically extracted and its active components was further purified. Toxicity test of the extract and active components on susceptibleCulex pipiens pallens,wild C. pipiens molestus and Aedes albopictus were performed using larvae immersion method. The LC50 of ethanol extract against larvae of C. pipiens pallens,C. pipiens molestus and A. albopictus during a 24 h exposure were 22.71,36.30 and 23.51 μg/mL,respectively. The major active component against A. albopictus was in Hexanephase,with a LC50 of 16.87 μg/mL. Whereas the ethyl acetatesoluble and water soluble components showed no lavicidal activity. Two subfractions H2 and H6,separated from hexane soluble phase with silica gel column chromatography,were the major active components. A 100% mortality of A. albopictus was observed at 25 μg/mL of H2 and H6 during a 24 h exposure. The results demonstrated that the active compounds from A. lancea were of high lavicidal activity against susceptible C. pipiens pallens,wild C. pipiens molestus and A. albopictus and had the potential to be developed as novel insecticide.