Abstract: In order to further improve egg white protein processing characteristics, egg white protein was modified by sodium tripolyphosphate (STP) , and some of its functional properties were discussed. Taking the phosphorylation degree as index, the optimum reaction parameters of egg white protein phosphorylation were determined by the single and orthogonal experiments. The result showed that the optimal parameters were temperature 30℃, pH8.0, heating time 3.5h, STP addition of 2.0%. Under these conditions, the phosphorylation degree was 60mg/g. Comparison of functional properties of before and after phosphorylated egg white protein, it was indicated that egg white protein solubility, water holding capacity, emulsification and emulsion stability were increased after phosphorylating modification. However, microstructure difference between before and after modification microstructure was not obvious by SEM.