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Tagetes minuta, as a newly invasive species in Tibet of China, its damage is beginning to appear. However, there are few studies on its invasion mechanism in China. In order to explore the biomass and its allocation characteristics of population modules of T. minuta in heterogeneous habitats, and to further understand its survival strategies and invasive habitats, we determined and analyzed the biomass characteristics and calculated the index values of phenotypic plasticity of the population modules in the flowering and fruiting stages of the T. minuta in five typical invasive habitats, including vegetable garden, orchard, roadside, wasteland and riverside. The results were as follows:(1)The basic law of biomass of module in T. minuta population was stem > flower and fruit > leaf > root. The biomass of each module was the largest in the roadside and the smallest in the vegetable garden, and there were significant differences between these two habitats(P<0.05).(2)The total coefficient of variation(CV)and phenotypic plasticity index(PI), based on maximum and minimum means of each module were 46.93% and 61.44%, respectively.(3)The relationship between biomass ratio of reproductive module and nutrient module of T. minuta was wasteland > roadside > orchard > riverside > vegetable garden, and the root-shoot ratio was vegetable garden > wasteland > riverside > roadside > orchard.(4)There were significantly positive correlation between biomass of different modules, between biomass of different modules and total biomass, which showed its ensemble and consistent strategy of survival. The above results indicate that T. minuta can adapt to heterogeneous habitats by adjusting the biomass of each module, and thus has a strong phenotypic plasticity. High reproductive output and adaptability to heterogeneous environments may be the important reasons for its successful invasion. [ABSTRACT FROM AUTHOR]