Thispaperdescribestherelativecontentsofdominantdiatomspeciesandthedistributivecharacteristicsoftropicalpelagicspeciesanddiatomassemblages,andalsodiscussestherelationsbetweentherelativecontentoftropicalpelagicspeciesandKuroshioCurrentandbetweenthedistributionofdiatomassemblagesandmaterialsources.Theresultsshowthatthelimitof>20%relativecontentoftropicalpelagicspeciesisbasicallyconsistentwiththedemarcationofKuroshioCurrent,andthatthedistributionsofdominantdiatomspeciesanddiatomassemblagesreservetherecordsoftheircloserrelationstomaterialsources.