The total fat content and fatty acid composition of 13 microalgae were analyzed.Results showed that fatty acid composition among different categories varied greatly.Chlorophyta contained 16C and 18C commonly.The fatty acid composition of Chromophyta were similar,among which Chrysophyta contains characteristics fatty acids such as 14:0,16:0,18:1,18:4 etc,while primary fatty acids of Phaeodactylum tricornutum are 14:0,16:0,16:1,16:3 and 20:5,the main fatty acids in Pinguiococcus pyrenoidosus were 14:0,16:0,20:5,and Porphyridium contains 16:0,20:4 and 20:5.Dunaliella salina had the highest proportions of Linolenic acid(about 60.9% of the total fatty acid).Isochrysis zhanjianggensis possessed the highest proportion of Parinaric acid(about 19.6% of the total fatty acid).The Arachidonic acid in Porphyridium and Eicosapentaenoic acid(EPA)in P.pyrenoidosus were about 17.1% and 20.9% of the total fatty acids respectively.