The harmful effects caused by alien invasive plants are becoming more severe under the background global warming and human interference in Yunnan Province. Research on the biological traits of alien invasive plants is an effective method to reduce the invasion risk and improve the prevention management. In this paper, we concluded that there were 247 alien invasive plant species in Yunnan, which belonged to 149 genus and 51 families based on literature reading, database and specimen records studying. The results showed that the dominated families of alien invasive plants were Compositae, Gramineas and Leguminosae in Yunnan, and more than half of the alien invasive plants originated from America. The biological characters of alien invasive plant were mainly annual or short-lived perennial herb, seed reproduction, main clonal reproduction is tiller. The time of flowering and fruiting mainly concentrated in summer or autumn. The dominant dispersal traits of the alien invasive plants depended on the special type/ color/ shape/ size/ surface structure and appendage of propagule, etc. We divided alien invasive plants into four grades based on the following five aspects: the distribution area in the county level of Yunnan Province, biological characteristics, harmful degree to the environment, whether listed in Top 100 the Worst Alien Invasive Species in the World and Four Batches of Alien Invasive Plant in China Jointly Issued by the State Environmental Protection Administration and Chinese Academy of Sciences. The four grades of alien invasive plants included 18 malignant, 23 serious, 188 general and 18 need to be observed species. The results showed that the malignant and serious alien invasive plants had high stable biological traits consistency with alien invasive plants in Yunnan. The problem caused by alien invasive plants in Yunnan is very serious with the increase of human disturbance to land. It is important to reduce the impact of invasive plants by understanding the biological traits and risk grade of alien invasive plants. The management ways of the alien invasive plants in Yunnan are also proposed through this study.