This paper reports eleven species of marine Cladophoraceae from XiSha Islands China. Ten of these species belong to the genus Cladophora, they were not reported previously in Xisha Islands, and six species of them are , new records in China. There is only one species of the genus Chaetomorpha being discovered from this region. All the materials for present study were collected by the colleagues of the Institute of Oceanography, ?cademia Sinica in the years 1957, 1958, 1975 and 1976.