Abstract Solidago decurrens is a plant of Asteraceae, which is mainly produced in southern China. It is widely used cut flower material. It is known as the malignant weed Solidago canadensis (Solidago canadensis) with the genus Flora, so its application of ecological security has been a big debate. In this paper, the allelopathic effect of the water extract of Solidago macrophylla was studied by using the micronucleus technique of Vicia faba root tip as the experimental material. The aim of this study was to analyze the genetic toxicity of Solidago canadensis. The results showed that: (1) The water extract of Solidago canadensis could decrease the mitotic index and interfere with the normal process of mitosis, where the decreased rate was positively correlated with the concentration of water extract and treatment time. (2) The effects of water extract on the root tip of Vicia faba were significant increases with time and concentration effect (3) Achilla glauca extract could make the chromosome bridge, chromosome fragment, chromosome lag in the root tip cells of Vicia faba and increase in micronucleus rate. The results showed that the water extract of Solidago canadensis had different degree of inhibition and damage to silkworm root tip cells; it also had some genetic toxicity and rapid diffusion ability.