In March to May, 1958, The present author had the opportunity to join the collecting party of the Institute of Oceanology, Academia Sinica, and had paid special attention to the fresh specimens of many echinoderms. This paper deals with the species of the Holothurioidea. A total of 425 specimens of holothurians were studied and 41 species belonging to 3 orders, 5 families and 16 genera were identified. Of these one species is new to science and 14 species are new additions to the fauna of China. A list of the species is given on pages 199-200, in which those marked with an asterisk are species recorded from China for the first time.