Abstract: Through the standard place names in the South China Sea Islands, the existential conditions of folk place names and the fishermen who named these have been surveyed to provide foundations for place naming planning, then provide evidence for safeguarding marine right and interests and maintain the marine safety. Reference to 〖WTBX〗Genglubus〖WTBZ〗, the islands named by the fishermen in the South China Sea have been examined. With a comparative study of folk and official islands names, and a research on the cognition of fishermen on these islands names, this study reveals that: (1)Folk place names recorded in 〖WTBX〗Genglubus〖WTBZ〗 have been transplanted into official place names published in 1983. This systematization from folk names to official names is in fact a protection to folk place names of the South China sea.(2)Distinction of the two place name systems is as follows: official place names use significant events or celebrities for commemoration, preserve public order and manageable possibility; folk place names use local things directly for practical use and provide convenience.(3)The persistence of folk place names is notable. As the practical users of islands names in South China Sea, the fishermen in Hainan can recognize both official and folk place names, but mainly use folk names especially within fishermen. In addition, the cognition region of place names by fishermen corresponds to their fishing area. Because of some limitations, the shrinking down of fishing area may cause cognitive deterioration of folk place names by fishermen. (4)In history period, affected by history or cultural factors, the connotation of place names often lags behind the practical circumstance. In contrast, the connotation of modern names often pulls ahead the practical circumstance mostly influenced by political or economic factors. However, coordination between connotation and circumstance is optimal. The islands names of South China Sea are simultaneously under influences of these two kinds (history or cultural and political or economic) and this made this area unique.