Objective： To investigate the effect of phosphorylation on nutritional value and digestion and absorption of whey protein isolate（WPI）. Methods： Phosphorylation of WPI by sodium tripolyphosphate（STP） was carried out. The emulsifying and emulsifying stability， foaming and foam stability， gel hardness and amino acid composition before and after modification were compared. In vitro simulated digestion model and Caco-2 cell absorption model were used to simulate digestion and absorption experiments. The digestion and absorption rate and amino acid composition of WPI before and after modification were determined and compared. Results： When the content of STP increased from 1% to 7%， the degree of modification increased with the increase of the amount of addition， and the functional properties of WPI increased significantly （P<0.05）. Threonine （Thr） and lysine （Lys） decreased with the increase of the degree of modification， but there was no significant difference in SRCAA among the modified groups. The digestion and absorption rate of WPI before and after phosphorylation modification was not significant difference（P>0.05）. Comparing the amino acid composition of WPI before and after phosphorylation modification， glutamic acid （glutamine） content was significantly decreased （P<0.05）， suggesting that glutamine may be a phosphorylation site other than lysine. Conclusion： Phosphorylation of WPI improve the functional properties of the same time， does not affect the nutritional value of protein and digestion and utilization.