The photosynthetic pigments of 12 species (14 strains) of cultured diatoms from six genera under specific conditions were examined by the HPLC.The diatom genera were Skeletonema,Thalassiosira,Chaetoceros,Nitzschia,Phaeodactylum and Meuniera.All strains were isolated from China seas and most of them were from the Jiaozhou Bay,China.Fifteen pigments were identified and eight of them were various chlorophyll a derivatives.Chlorophyll a,c2 and c1 and the carotenoids fucoxanthin,diadinoxanthin,diatoxanthin and β,β-carotene existed in all species.The ratios of each pigment to chlorophyll a were compared with the results in literatures.The pigment ratios of this study generally fall within the ranges reported by the literatures although the maximum ratio of fucoxanthin to chlorophyll a was higher and the ratios of chlorophyll c and diatoxanthin to chlorophyll a were low.The pigment ratios are useful to understanding the pigment signatures of diatoms in the Jiaozhou Bay,China,and to setting up the chemotaxonomic method ofphytoplankton in these sea areas.