Abstract:In this paper the authors report on the biological characteristics of Al-sophila spinulosa (Hook.) Tryon. The reasons of endangering of this plant as follows: The life of the spores is too more short and the spores are very difficult to germinate. The biocycle from spore-prothallus-sporophyte is too long. They are very difficult to resist and tolerate adverse factors in variousenvironment.It needs a strict habitat for spore germination gamete differentiation and embryogenesis. Therefore the distribution region is highly limited. And it is most suitable for Alsophila spinulosa to exist in the worm and humid tropical and subtropical forest under the contemporary climatic condition.