Trefoil factor family (TFF) peptides have a special domain called trefoil domain. Trefoil domain contains highly conserved cysteine, arginine, glycine, tryptophane, phenylalanine and a unique three-loop structure which is formed by intrachain disulfide bonds between six conserved cysteine residues in the 1～5, 2～4, 3～6 position. Three most important TFF peptides are TFF1/pS2, TFF2/SP (spasmolytic polypeptide) and TFF3/ITF (intestinal trefoil factor). The ectopically expressed sites of them are body and fundus of stomach, deep foveolar pits of gastric antrum and goblet cell of small and large intestine, respectively. TFF may play an important role in both maintaining the barrier function of mucosal surfaces and facilitating healing after injury. The structures of TFF peptides are very compact and contain α-helix，β-sheet. The mechanism of TFF is not clear and two hypotheses were proposed which were co-working with mucin or receptor.