Abstract: In vitro digestion of proteins in two infant formulas and one moderately hydrolyzed protein infant formula were conducted in a simulated digestion environment of infants, and human milk was used as control. The in vitro gastric, intestinal and total digestibility of proteins and the content of amino acids in digestive juice were measured.The results showed that the in vitro gastric, intestinal and total digestibility of proteins were in the order of human milk > moderately hydrolyzed protein infant formula > infant formula B > infant formula A, and the digestibility of proteins in human milk was significantly higher than that in moderately hydrolyzed protein infant formula and two infant formulas ( p < 0.05) .Additionally, the content of essential amino acids in total digestive juice for moderately hydrolyzed protein infant formula was significantly higher than that in human milk and two infant formulas ( p < 0.05) . The content of total amino acids for human milk and moderately hydrolyzed protein infant formula was significantly higher than that in two infant formulas ( p < 0.05) .Compared with the two infant formulas, proteins in moderately hydrolyzed protein infant formula are nutritional due to easy digestion and utilization.