The present study is based on the collection from the Xisha Islands in May 1974 and April-may, 1975, of which 24 species are identified. With the exception of Collosphaera planca Su and Siphonosphaera arks Su, all are recorded for the first time from this investigation area.As the majority of these species have been described for the adjacent waters, we give only the description of those species which are first records for Chinese waters. Most of colonial radiolaria of the Xisha Islands are distributed in the surface waters.The frequency of occurrence of the different species varies. Some species as Otosphaera auriculata, Siphonosphaera polysiphonia, Acrosphaera spinosa, Collosphaera huxleyi, Siphonosphaera tenera, Solenosphaera pandora, and Solenosphaera zanguebarica are found at more than six stations, the rest at less than five stations or at only one station. Seven species are found in Jinyin Island and the northwestern part of the investigated area. As the colonial radiolaria of the Xisha Islands are mostly found in the surface waters,their quantitative distribution is closely related to the distribution of surface water temperature.