Abstract: Egg white protein powder is one of the commonly used excipients in flour product processing. To investigate its effects of egg white protein powder on dough characteristics, noodle quality, and in vitro estimated glycemic index (eGI), different proportions of egg white protein powder were added to flour in this study. The effects of egg white protein powder on dough mixing properties, bubbling properties, pasting, noodle cooking, textural, sensory properties, and eGI were studied. The results showed that the addition of egg white protein powder reduced the water absorption and development time of the dough, with the stabilizing time achieving the best effect at a 5% addition level. The bubbling properties, including P (maximum pressure), L (mean abscissa of rupture point), and W (energy), reached 1 510.19 Pa, 34.4 mm, and 17.34 mJ, respectively, at a 5% addition level. The viscosity index of the blended flour generally showed a decreasing trend, while the increase observed at a 5% addition level was beneficial for improving the product’s palatability. The gelatinization temperature of the blended flour increased, reaching a maximum of 85.75 ℃. The optimal cooking time, water absorption index, hardness, chewiness, tensile force, shear force, and toughness of noodles gradually increased with the addition of egg white protein powder. The cooking loss rate and extensibility of noodles exhibited the best quality at a 5% addition level, with the noodles also receiving the highest sensory score and high acceptability. The eGI value of noodles decreased with the increase in egg white protein powder addition, achieving a 19.71% reduction compared with regular noodles when the addition level was 15%. Microstructure observations revealed that the introduction of egg white protein powder increased the protein network structure in the dough, with more starch grains distributed within it, resulting in a more continuous and the denser internal structure of the noodles. Comprehensive analysis indicated that the optimal addition level of egg white protein powder was 5%, at which point the eGI value of noodles was reduced by 11.23% compared with noodles without egg white protein powder addition.