Chenopodium ambrosioides L., one of the aromatic herbaceous species of the Chenopodium genus, native to tropical America, has become major invasive plant in China. It was first recorded in Tamsui, Taipei County in 1864. Since then, it has spread extremely rapidly, now it can be found in Shandong, Shanxi, Zhejiang, Jiangxi, Fujian, Taiwan, Guangdong, Hainan, Hunan, Hubei, Guizhou, Yunnan, Sichuan Provinces, the Guangxi Zhuang Autonomous Region, Beijing, shanghai, Chongqing and Hongkong cities, posing threat to local biodiversity and economics. It is extremely difficult to control or eradicate C. ambrosioides. Allelopathy is one of the mechanisms by which invasive alien species invade successfully. Invasive plant may release allelochemicals into the environment by leaching, root exudation, volatilization, residue decomposition and other processes. Allelopathy of these allelochemicals could be achieved by soil media. The volatile oil from C. ambrosioides was extracted by steam distillation, and genetic toxicity and apoptosis of root tip cells of V. faba induced by volatile oil in soil were investigated using V. faba root tip micronucleus assays and DNA ladder analysis technique. The resulted showed that lower dose (5 μL) volatile oil promoted root growth and mitosis of root tip cells of V. faba, but root growth and mitotic indexes were inhibited with the increase of dose (>5 μL) and prolonging of action time. The aberrant chromosomes of V. faba root tip cells such as micronucleus, chromosome bridge, chromosome break, chromosome lag, chromosome conglutination, chromosome loop and multi-pole divide induced by the volatile oil in soil were observed. The volatile oil from C. ambrosioides was shown to induce increased micronucleus frequency of root tip cells, but this increased effect gradually decreased along with the increasing dose of volatile oil. DNA ladder analysis of root tip cells revealed that volatile oil can induce apoptosis, in a dose-and time-dependent manner. The progressive delineation of fragmented DNA was coincident with the appearance of DNA ladder was observed after being exposed to >15 μL volatile oil for 48 h and >15 μL volatile oil for 72 h. These results suggested that the volatile oil from C. ambrosioides was shown to be with significant allelopathic potential on root cells mediated by soil.