Many investigations revealed that, because of different biophysical and biochemical properties of different ingredients of plasma membrane, they are phase-separated into local domains. Different domains may have different functions. In the past few years, a special kind of cholesterol, sphingolipids, receptor and signal molecules-rich liquid-ordered domain，lipid rafts，which have been implicated in processes as diverse as signal transduction, cell sort, endocytosis and cholesterol trafficking, have been paid much attention. Hereupon, primary progress has been made in fundamental investigations on the structure and function of lipid rafts.