The study of phytocenotic and bioecological features of phytoinvasions allows to better understand the nature of these plants and develop quarantine measures to limit their activity.The article provides phytocenotic and bioecological characteristics of Xanthium strumarium L. in Quba and Khachmaz regions. It has been established that X. strumarium occurs along roadsides, railways, on wastelands, and also forms communities on forest outskirts, along open water channels and along the coastlines of the Caspian. The communities with the dominance of X. strumarium described in natural habitats are characterized by us as groupings, associations, and formations. The species is invasive. The study of the underground part of the plant showed that its root system can change depending on the soil moisture regime. Plant with taproot of 10-20 cm grows on dry and periodically humidified due to moisture of atmospheric precipitation areas (wastelands, roadside strips, household plots, light forest coenoses). Reproduction is exclusively by seed. In areas with high or “swampy” type of moisture and salinity (riverine strip, coastal sands, ditches, water channels, etc.), the root system is located in the upper soil horizon (5-10 cm), numerous root shoots of 30-40 cm long extend from the main root. In this case, reproduction can occur both interchangeably and vegetatively. The invasive activity of the species is facilitated by the features of biology: the efficiency of seed distribution, the ability to vegetative reproduction, resistance to all forms of anthropogenic impact, and wide ecological amplitude. In spite of this, the invasive activity of X. strumarium is limited by vertical zoning and by more highly competitive invasive species ‒ Amaranthus retroflexus, Xanthium spinozum.