In order to understand the current situation of alien plants in South China, 223 species of alien plants belonging to 141 genera and 45 families were identified by field investigation and literature review, mainly composed of Asteraceae (38 species), Fabaceae (36 species) and Poaceae (19 species). The herbs and plants native to the Americas dominated, with 204 herbs (91.5% of the total) and 163 plants (73.1%), respectively. There were 159 invasive and 23 naturalized plants in Guangdong, 135 invasive and 16 naturalized plants in Guangxi, 111 invasive and 15 naturalized species in Hainan, 105 invasive and 9 naturalized plants in Hong Kong, 89 invasive and 4 naturalized species in Macao. Among them, there are 57 alien invasive and naturalized plants commonly distributed in the 5 provinces and regions of South China (55 invasive and 2 naturalized species). Guangdong has the largest number of alien species, meantime, and the largest number of alien invasive and naturalized species share with the other four provinces and regions, indicating that Guangdong is the major input and output province for alien plants. Due to the similarity of climate and ecological habitats in South China, each province is at risk of invasion by other species from surrounding areas, therefore, when controlling invasive plants, joint monitoring, prevention and control mechanism should be established, so as to improve the control efficiency of alien invasive plants and reduce the threat to human health and ecological safety.