Abstract: The lipid compositions of Porphyra haitanensis were rapidly identified by ultra performance liquid chromatography-time of flight-mass spectrometry (UPLC-Q-TOF-MS). With acetonitrile, methanol, isopropyl alcohol and water as gradient eluents, the total lipids extracted from Porphyra haitanensis were separated by Waters Acquity UPLC^TM BEH C8 column. In addition, based on tandem mass spectra, the position of acyl chain, length and unsaturation of lipid chain were identified, which could be useful for lipid composition characterization. The results show that Porphyra haitanensis contains glycolipids (DGDG, Lyso-DGDG, MGDG, SQDG and Lyso-SQDG), phospholipids (PG, Lyso-PG and Lyso-PC) and triglycerides. The method has well application in qualitative and quantitative analyses of lipids from Porphyra haitanensis.