Abstract:Tithonia diversifolia (Hemsl.) A.Gray (Asteraceae), a native of Mexico and Center America, has long been cultivated in China as an ornamental and green manure plant. It first became naturalized in south Yunnan Province ca. 1930, and it is now recognized as a damaging invasive species in the tropical, southern and central sub-tropical regions of China. In order to understand its methods of dispersal and invasive potential, six biological indexes \[infructescence diameter, seed (achene) number per infructescence, seed set, 1000-seed weight, seed length and width\] were analyzed among T. diversifolia populations in five geographically and climatically different areas. Seed germination at 15, 20, 25, 30℃ and 35℃ was also tested. All six biological indexes were significantly different（p＜0.01）among the five populations. Seed germination rate among the five populations was also significantly different (p＜0.01 respectively at 15℃, 20℃, 25℃ and 30℃ but p＜0.05 at 35℃). The highest seed germination rate from each of the five populations was also significantly different (p < 0.01). Several conclusions can be drawn, based on these results and our previous studies of the cloning ability of T. diversifolia and its role natural communities. ①Although the seed reproductive characteristics among the T. diversifolia populations are significantly different, the species’ role in communities and its potential for damage are similar. ②The great reproductive capacity of T. diversifolia combined with its strong clonal growth facilitates its ability to become a community dominant, once it enters a new range via dispersal by animals, transportation networks and rivers.