Ultrasonic-assisted glycosylation technology (ultrasonic power: 300 W) was employed in this study to conjugate inulin with Antarctic krill protein (AKP), via pH-shift glycosylation modification under pH 11.0, and changes in the functional properties of the modified AKP were examined. Overall, ultrasonic duration significantly affected the emulsifying properties of inulin and AKP. In particular, ultrasonic treatment for 20 min (AKP-pH11-U20) resulted in increased emulsifying activity index (EAI) and emulsifying stability index (ESI) of AKP, reaching 56.93 and 5.63 m²•g−1, respectively, whereas the foaming characteristic (FC) and foam stability (FS) were of 35.87% and 31.87%, respectively. The constructed emulsion exhibited a uniform particle size distribution (148.60 nm, PDI<0.2) and good stability (Zeta potential: −49.97 mV). In vitro simulated digestion studies demonstrated that the particle size (142.05 nm) and Zeta potential (−39.61 mV) of the emulsion in the AKP-pH11-U20 group were reduced by 63.83% and 72.32%, respectively, after intestinal digestion, indicating a significant improvement in its digestive utilization. In conclusion, an appropriate ultrasonic duration can significantly enhance the emulsifying and digestive properties of pH-shift glycosylated AKP, which provides a theoretical basis and technical support for the high-value utilization of AKP and the development of functional emulsion delivery systems.