In order to improve the gelling property of egg white powder(EWP),sodium tripolyph-osphate(STP) was used to modify EWP.Sodium tripolyph-osphate substitutability,heating time and temperature were studied as three factors on gel strength of egg white powder.On the basis of single factor experiment,the conditions of phosphorylation modification were optimized by the response surface method.Research results showed that the optimization conditions were: STP substitutability 0.5%,reaction temperature 35℃ and reaction time 4 h.Under such conditions,the gel strength was increased 2.37 times from 308g/cm2 to 730.392g/cm2.