Seven marine microalgae species (Isochrysis galbana 3011, I. galbana 3018, I. galbana 3009, Pavlova viridis 3012, Nitzschia closterium 2034, Phaeodactylum tricornutum 2038 and Chlorella sp.) widely used as live feed in aquaculture, were laboratory cultured separately under identical culture conditions for two weeks, and then analyzed for the compositions of lipids and fatty acids in them. The total lipid contents of the algae (excepting N. closterium ) were ＞10%，and the highest (26.6%) one was in I. galbana 3009. The polar lipid contents in the total lipids were 27.2%-66.5%, and the n3-polyunsaturated fatty acid contents were 29.3%-61.3% of total fatty acids.