Trypsin is a serine protease from the PA clan superfamily, found in the digestive system of many vertebrates, where it hydrolyzes proteins. Trypsin cuts peptide chains mainly at the carboxyl side of the amino acids lysine or arginine. It is used for numerous biotechnological processes. The connection between animal cells is a specific connection formed by the differentiation of the plasma membrane (cell membrane) between adjacent cells. The plasma membrane is mostly composed of protein-lipid-protein unit membrane, and the proteins on the plasma membrane are mostly involved in the connection. Thus, the digestion of adherent cells HepG2 was to detect the bioactivity of recombint pig trypsin. HepG2 cells were seeded into 96-well plates at a density of 4,000 cells/well with 10% serum standard DMEM overnight. Various concentrations of recombinant pig trypsin was added into the HepG2 after washed by PBS buffer. Cells were observed by inverted microscope after a period of time cultured at 37℃. The result was shown in Figure 1. It was obvious that recombinant pig trypsin can digest the HepG2, the minimum protein concentration was 46.9 ug/ml.