Cephalaspidea is one of the primitive group of Opisthobranchia, Gastropoda,Mollusca and is particularly common in tropical and subtropical waters of the Indo-Pacifio region. The Cephalaspidea fauna of China is mainly composed of tropical and subtropical species, and also a lot of temperate species, but no cold water and circumtropical species have been found. It is closely related to that of Southern Japan fauna. Among the 145 species and subspecies of Cephalaspidea found in the China Sea.45 species are found in the Bohai Sea-Yellow Sea, which mainly of temperate species; 66 species mainly composed of warm species and a lot of temperate species are found in the East hina Sea; 104 species occurring in the South China Sea are composed of tropical and subtropical species, the temperate species reduced.