Abstract: Spores of the Microsoirum fortunei (Moore) Ching were cultured in the inorganic medium and the soil respectively. Spore germination and gametophytic development were observed by microscope. Our observation showed that the spores are yellowish, monolete, with the exine bearing a spinulose ornamentation, and bean-shaped in equatorial view and elliptical in polar view. The spores germinated within 7-12 days after inoculated in the medium, the germination was of the Vittaria-type while the gametophyte development was of the Drynaria-type. The prothallial plates formed with in 25 days after inoculation. The establishment of an apical cell was delayed, and some prothalli omitted the meristematic cell. Vegetative propagation often occurred on the basal part of the prothallial plate in the inorganic medium. Further development after the formation of the prothallial plate and profuse unicellular hairs occurred on both surfaces and margin of the prothalli. Young prothalli developed within 60 days after inoculation and mature prothalli were of cordate-thalloid. The sex organs were formed in 80 days after inoculation, and antheridia appeared about 10 days earlier than archegonia. Archegonial neck usually inclined or curved towards the base of the prothallus at maturity.