Abstract: Dark tea, a post-fermentation tea, is a kind of peculiar tea with a long history in China and is mainly produced in provinces of Hunan, Hubei, Sichuan, Yunnan and Guangxi. Fresh raw leaves from tea tree processed by fixing, rolling, pile-fermentation, and baking become dark tea. Pile-fermentation is a unique process for production of dark tea as well as the key process for forming the quality of dark tea. A series of complex chemical changes make substances withinleaves turn into quality ingredients of dark tea with unique color, aroma and taste during pile-fermentation. In this paper,the research on microorganism, biochemical components, enzymatic activity and regulation technology during pile -fermentation were reviewed in the recent ten years, and the research emphasis of pile-fermentation of dark tea in the future was also put forward.