Abstract: Tannins are a heterogeneous group of high molecular weight, water-soluble polyphenolic compounds, widely distribute in various parts of plant, they can be intake by human in the form of dietary polyphenols. Tannins can be divided into two major categories, hydrolyzed tannins and condensed tannins (proanthocyanidins), with highly biological activities such as antioxidant activity, inhibition of cancer, anti-bacterial activity, cardiovascular disease prevention. In this paper, the advances in research on absorption, metabolism and biological activity of tannins were reviewed to provide some reference for the study of plant tannins.