In order to investigate the growth characteristics of invasive plant Ageratum conyzoides at the level of population module, and understand its survival strategies and invasiveness, the module biomass, the correlation among module biomass as well as, the ratios of reproductive module biomass/nutritional module biomass and of root/shoot were measured to determine its module biomass allocation in four different habitats (i.e. Ⅰ front or behind house, Ⅱ vegetable farm, Ⅲ orange orchard and Ⅳ roadside). The results showed that, the module biomass of A. conyzoides in different habitats was different but it had same trendency, i.e. stem > leaf > root > flower and fruit. The total biomass and the biomass of stem, leaf, flower and fruit in habitat Ⅱ were the highest, the lowest in habitat Ⅳ, and there were significant differences between these two habitats (P < 0.05). The subsequence of module biomass allocation was inconsistent with that of module biomass in different habitats, and the differences for the former were less than those for the later. The ratios of reproductive module biomass/nutritional module biomass in four habitats followed as the subsequence of Ⅳ > Ⅲ > Ⅱ > Ⅰ, with the values of 0.069, 0.061, 0.050 and 0.042 respectively, the root/shoot ratios followed as the subsequence of Ⅲ > Ⅰ > Ⅳ > Ⅱ, with the values of 0.211, 0.179, 0.154 and 0.090 respectively. There were highly significant positive correlation between plant height and module biomass, among biomass of different modules of A. conyzoides (P < 0.01). For the correlation between plant height and module biomass, the correlation between plant height and stem biomass was the strongest with the correlation coefficient of 0.525; for the correlation among biomass of different modules, the correlation coefficient between stem biomass and leaf, flower and fruit biomass was above 0.900. The differences of module biomass, ratios of reproductive module biomass/nutritional module biomass and root/shoot of A. conyzoides in different habitats suggested its strong phenotype plasticity and adaptability to heterogeneous habitats, which may enhance its invasiveness. The same trends and relatively lower differences among module biomass of A. conyzoides in different habitats indicated the relative stability of biomass allocation patterns. The highly significant correlation among the modules of A. conyzoides population showed its integrity strategy of survival.