Abstract: The species composition, origin and faunal composition of alien invasive plants in the green space of the main urban park in Chongqing were analyzed. The results showed that there were 41 species of alien invasive plants belonging to 34 genera and 19 families in the green spaces of Chongqing's main urban parks. Among them, garden invasive plants belonged to 17 species belonging to 15 genera and 11 families, and garden invasive weeds belonged to 24 species belonging to 19 genera and 10 families, the rest were weeds, the most were species of Asteraceae; In terms of origin, 33 species are from America, the largest number of species, and the rest are from Europe, Asia, Africa, etc. In terms of family composition, single species and small family constituted the main body of alien invasive plant family in the green space of chongqing main city park. In terms of floristic composition, the floristic composition of both families and genera has obvious tropical floristic characteristics.

Key words: alien invasive plants, the green space of the main urban park green, Chongqing city