Intact Polar Lipids (IPLs) are synthesized predominately or uniquely by specific organisms and would degrade rapidly after cell death. Such biomarker IPLs can be used to indicate the microbial distribution and activity in marine environment. Here the progress of the aforementioned studies made over the last decade was reviewed. With the development of chromatography and mass spectrometry, the discovery of new IPLs compounds and the application of stable carbon isotope composition (δ¹³C) of IPLs, our understanding of the composition and transformation of IPLs in suspended particulate matter in the water column and of the applicability of the TEX₈₆ proxy are greatly improved. Besides, IPLs are widely applied in the study of marine eukaryotes-bacteria symbiosis, aerobic and anaerobic ammonia oxidation, anaerobic methane oxidation and microbial metabolic states. Meanwhile, it is suggested by recent studies that different IPLs often exhibit differential degradation. Some IPLs, especially glycolipids, have the potential to be preserved as fossil molecules for very long time upon dead cells, and therefore, they can not specifically indicate living biomass. Furthermore, the IPLs degradation rate and completeness would be affected by such factors as oxygen concentration and organic matter content. It is also suggested that the composition of IPLs might be affected by microbial metabolism. Therefore, it is essential to take these factors into account when IPLs are used as proxies to trace marine microbial activities and reconstruct the palaeoenvironment.