Abstract: Dark tea is one of the six Chinese tea,and contains Yunnan Pu- erh tea,Hunan Fu- zhuan tea,Hubei Qing- zhuan tea,Sichuan Bian- xiao tea and Guangxi Liu- bao tea.Mold,bacteria,yeast and other microorganisms play an important role,in the process of dark tea post fermentation.Through the extracellular secretion of enzymes and heat effect,catechins and polyphenols and other ingredients will start biochemical reactions such as oxidation,decomposition,aggregation and transformation,which eventually developed the unique quality of dark tea.Terpene alcohols compounds,alcohols,ketones and aldehydes and other substances are the main components of the formation of dark tea aroma. Dark tea regulates blood lipids by adjusting the metabolism of cholesterol and triglycerides.In addition,catechins in dark tea can inhibit fatty acid synthase( FAS) and other fat synthesis related enzyme activity in order to reduce the level of fat synthesis.