Abstract: The characteristics of Reproductive Ecology was studied and discussed the endangered reason of Rhodiola sachalinensis.There are four sporangiates in the anthers of this species, and the tapetum was of the glandular type.The primary sporogenous cells functioned directly as microspore mother cells.Tetrads were tetrahedral, and mature pollen grains contained two cells.There are some microsporophytes infertile during their occurrence and two types of mature pollen.Ovules were anatropous.The terad of megaspores was linear, with the first cell from the chalazal end being functional.The development of embryo sacs belongs to the polygonum type.Pollen infertile is one of the internal causes for endangerment, the external factors are the adverse environment and it's over-collected by people.

Key words: Rhodiola sachalinensis, Formation of microspores and megaspores, Environment condition, Endange