The present paper is the third part of a.report on the echinoderms of Xisha Islands-Echinoidea. The material for study was based on the collections made by the Institute of Oceanology, Academia Sinica during 1956-1958 and1975.A total number of 192 specimens of echinoids was examined. Twenty-six species,including three subspecies belonging to 21 genera, 13 families and 7 orders were identified. Of these one species is new to science and 8 species are new additions to the fauna of China. A list of the species is given on pages 101 in which those marked with an asterisk are the species recorded from China for the first time. As to the system of classisication,we have followed T. Mortensen in his wellknown work ‘Monograph of the Echinoidea'.