[Aim] Tagetes minuta L. is an annual alien plant introduced from South America to many areas of China, and is currently causing ecological damage. The aim of this paper was to analyze the ecological adaptive characteristics of T. minuta and propose the risk index system to determine its risk level.[Method] The distribution, level of hazard and biological characteristics of T. minuta were investigated. The ecological adaptability of T. minuta was qualitatively analyzed, and the ecological risk was quantitatively analyzed.[Result] The risk value of T. minuta was R=80>61 according to the evaluation of the risk indicator system (R₁=83, R₂=88, R₃=65, R₄=84), indicating that T. minuta was agressive invasive species.[Conclusion] T. minuta should be strictly prohibited. Since T. minuta has been disseminated to China, it's necessary to carry out emergency measures to quarantine, monitor and eradicate, and prevent its spread into other areas of China.