Abstract:Based on field investigation and literature consultation, seventy three species of alien invasive plants belonging to 59 genera of 27 families were identified in Guangzhou. Of them, nineteen alien invasive species belonging to Asteraceae, eight to Poaceae, and seven to Fabaceae and Amaranthaceae respectively, and they take up 56.2% of the total number of the invasive plants in Guangzhou. With respect to the life form of alien invasive plants distributed in Guangzhou, the most dominant plant are terrestrial herbs (58 species), then shrubs (10 species), aquatic herbs (3 species) and trees (2 species), which distributed in the area of heavily disturbed and low altitude. In addition, based on the growing, dispersal status and other ecological features of the invasive plants in the field, eleven alien invasive species were evaluated to be at the highest degree of threat to the local biodiversity, twenty five at the medium, and 37 at the lowest. Constitutional analysis of the original locality of the alien invasive species revealed that 61 species were from tropical America and took up 83.6% of the total species in Guangzhou. Comparing with other domestic regions in terms of the number of the alien invasive plants, Guangzhou and Guangxi share the most and have 62 species. However, concerning the species that have caused serious threat to local biodiversity, Guangzhou shared eight species with Hong Kong, seven species with Shenzhen, and six species with Guangxi. Moreover, we also evaluated the potential threat for those alien plants that grow in Guangzhou and have caused serious biodiversity damages in other domestic regions. Our result reveals that the government should pay much attention to monitoring these invasive species so as to prevent them from dispersing and causing ecology disaster in Guangzhou. Furthermore, the invasive pathways and preventive strategies of alien plants are also summarized here.