Abstract: The plant configuration during the construction process of villages and towns and the ecological restoration of the land space has a certain potential impact on the regional ecological security and the health of the human settlement environment, especially the alien plants are prone to intrusion risks and harms. In order to grasp the composition, distribution and ecological risks of alien plants in the construction of villages and towns in the Chishui River Basin, Guizhou Province, we selected a certain valley-type town, 49 sample sites were set up in built-up and non-built-up areas. In this work, the species composition, distribution characteristics and topographical factors of alien plants were investigated, and the analytic hierarchy process (AHP) was applied to evaluate the invasion risk of 37 kinds of alien plants. The results show that: (1) A total of 276 species of plants, belonging to 230 genera and 99 families, were found in this valley-type town. Among them, there were 37 species of alien plants, which belong to 18 families and 32 genera. The number of herbaceous plants is the largest, accounting for 64.9% of the total number of alien plants. And 22 species of alien plants were from America. (2) The main distribution range of the alien plants was 400-650 m above the sea level. There was a significant positive correlation between the number of alien plant species and the invasion intensity (P < 0.01), and a significant negative correlation between the altitude and the number of native plants (P < 0.01). Altitude had the greatest influence on the number of alien plants, with a contribution rate of 68.7%. The contribution rates of invasion intensity and native plant species number were 12.4% and 9.6%, respectively. (3) Among the 37 species of alien plants, 13 species (accounting for 35.1%) had high level of risk invasion, including Conyza canadensis L. Cronq. (S7), Amaranthus retroflexus L. (S1), Bidens pilosa L. (S2) and Ysphania ambrosioides L. (S4) and so on, and 13 species had medium level and 10 species had low level of risk invasion. The research shows that the distribution of alien plants in this valley-type town was affected by altitude and native plants. There were more alien plants in low -altitude areas and 13 species of alien plants had a high level of invasion risk. There was no significant difference in the distributions of built-up areas and non-built-up areas. The research results provide a basis for the prevention and control of ecological risks of alien plants with high invasion risk levels, and for the rational development and utilization of native plants in this valley-type town.