This research explores the risk assessment and effective management strategy of invasive alien species Tetrapanax papyriferus which is cultivated widely in Yugawara, Kanagawa Prefecture. We surveyed its habitat, spatial distribution, and community distribution in order to classify the vegetation landscape units following the phytosociology method. And then we used two risk assessment models to verify invasive potentialness: Pheloung model (1999) and Linda&John model, to assess invasiveness before exotic species are introduced and after are introduced, respectively. In Pheloung model (1999), the total scores are 16 which mean the alien species are prohibited to be introduced. In Linda&John model, T.papyriferus scored 0.64, which means it was assessed to be highly invasive. The best management strategy is to choose the best effective method to eliminate, simultaneously to stop or slow the spread into the new areas. To achieve it one should consider many factors such as the seed dispersal and the time. Tetrapanax papyriferus is adapted to the abandon field, slope, and talus cone which are mostly created by human actions, so it is essential to provide the risk information of T.papyriferus to nearby resident for help degradation.