The Institute of Oceanology, Academia Sinica, during 1956, 1957, 1975, 1976, 1980，carried out five scientific surveys on about twenty isles of the Xisha Islands. Morphological and systematic studies were made on the basis of the materials collected from the above surveys. With the exception of 14 species and 4 forms, already reported from the Xisha Islands, [1,2,3] the other 6 species and 3 forms, namely, Leptophytum asperulum (Fosl ) Adey, Hydrolithon boergesenii (Fosl) Fosl, Lithoporella pacifica (Heydr ) Fosl, Neogoniolithon megalocystum ( Fosl ) Setchell et Mason, Porolithon onkodes (Heydr.) Fosl. f. subramosa Fosl and f devia Fosl, Lithophyllum okamurai Fosl, Amphiroa fragilissima (Linn) Lamx.f. cyathifera (Lamx )Weber van Bosse, Jania capillacea Harvey, are recorded to be new to China.In this paper,the record of tetrasporophyte in Neogoniolithon pacificum (Fosl )Setchell et Mason is supplemented for the Chinese marine flora. Most of the species are of tropical and subtropical algae and found in the Indian Ocean and the Pacific Ocean. Among them, Porolithon nokodes, Neogoniolithon variabile and Neogoniolithon frutescens are particularly abundant, Hydrolithon reinboldii and Neogoniolithon trichotomum can also be found readily. Up to the present, 20 species and 7 forms of Corallinaceae have been reported, but the total number of species on the Xisha Islands may be over 40. It is because that the specimens of some species used for study were rare, others with reproductive organs, especially the asexual reproductive organs were lacking or scarce,in addition, epiphytic and deep water species needed further study. The above facts have shown that the Xisha Islands have a rich corallinaceous algal flora.