Abstract: Guizhou province, located in the southwest China, is one of the richest biodiversity regions, meanwhile, is also one of the hardest-hit areas by alien invasive species. A comprehensive understanding of the invasive alien plants species composition and distribution can provide a scientific basis for the prevention, early warning and integrated management, to improve the ability of alien invasive species prevention and control. In this study, Guanling Buyi and Miao autonomous county, located in the central Guizhou province, and Huishui county, located in the south-central Guizhou province were selected as the investigation sites. Investigation was conducted in 74 sampling sites of Guanling county and 64 sampling sites of Huishui county using quadrat sampling method, to figure out the species composition, obtain the distribution pattern information (habitats and distribution frequency), then analyze their origin, life type by referring to the literature. In this study, 24 families 56 species of agricultural alien invasive plants were found through field investigation, among which Asteraceae was the dominant family (Guanling: 29.55%, Huishui: 33.33%), followed by Amaranthaceae (Guanling: 13.64%, Huishui: 11.11%), Fabaceae (Guanling: 6.82%, Huishui: 6.67%), Solanaceae (Guanling: 6.82%, Huishui: 4.44%), with mainly herbaceous species (Guanling: 80.85%, Huishui: 86.96%). The escaped Verbena bonariensis Linnaeus and Myriophyllum aquaticum Verdcourt were found in Guizhou for the first time in the wild, confirming their invasive characteristics. Furthermore, Ageratina adenophora (Sprengel) R. M. King & H. Robinson, Bidens pilosa Linnaeus, Erigeron annuus (Linnaeus) Persoon, Alternanthera philoxeroides (Martius) Grisebach, Erigeron canadensis Linnaeus, Geranium carolinianum Linnaeus, Galinsoga parviflora Cavanilles were classified as malignant agricultural alien invasive plants in these two counties, which widely distributing in the sampling sites. Agricultural alien invasive plants had adapted to various habitats and mainly distributed in the frequently anthropogenic disturbance habitats including wastelands, farmlands, roadsides, which had caused threats to the agroecosystem, human activities and natural ecosystems. The alien invasive plants has great species diversity, wild distribution range, strong adaptability, fast reproduction speed and strong reproductive ability in this two counties. Authors suggest that people should take the systematically investigation of the agricultural alien invasive plants in Guizhou province, and strengthen the monitoring and dynamic spread trend research of malignant alien invasive species, to provide scientific basis for the prevention, early warning and integrated management of alien invasive plants.

Key words: Guizhou province, Agricultural alien invasive plants, Species composition, Distribution pattern, Characteristics analysis