Abstract: Crofton weed (Eupatorium adenophorum) is one of the worst invasive species in China，and there is the risk of invasive Huazhong area according to the existing route. In order to analyse the responses of phenotypic varying in introduced ranges, populations of crofton weed collected from Xichang in 2009 and 2012 were planted in a field common-garden. The growth parameters such as plant height, stem diameter, specific leaf area, leaf dry matter content, as well as the resistance to Fabricius（Prodenia litura）, were compared between cutting seedlings of the two populations. The results showed that the leaf C/N ratios of Eupatorium adenophorum were similar beween the two populations, however, plant height, stem diameter and the insect resistance were highly significantly higher in 3-year population than 1-year population, showing obvious phenotypic plasticity; specific leaf area increased significantly with the time of introducing prolonged, while leaf dry matter content significantly reduced. The survival strategy and the competition ability for the above space in plant can be reflected though the combination of plant height and some leaf characters, larger plants meaning with more resources. With the extending of introduction time, there have enhanced in the adapation ability, accessing to resources and insect resistance for generalist herbivory in the introduced range as well as no-specialists. As low matter content for defence against generalists herbivores and low-cost for synthesis, the plant use more resources to grow. therefore, in the process of E. adenophorum control we should be introduce natural enemies and chemical control in the early invasion, we may control its spread more effectively.