This study aimed to develop a quercetin-loaded whey protein complex using pH-induced co-assembly for the intestinal-targeted delivery of quercetin. The investigation focused on quercetin loading capacity, formation mechanism, stability, antioxidant activity, and in vitro digestive properties of the complex. The results indicated that the stable complex was obtained at a quercetin-to-protein mass ratio of 1:20, exhibiting a high encapsulation efficiency (96.4 %) and loading capacity (4.6 %). Interaction studies revealed that quercetin binds to whey protein via hydrophobic interactions and hydrogen bonding, forming an irregular layered structure. Stability analysis demonstrated that the complex possesses high ionic and thermal stability. The antioxidant capacity of quercetin was significantly enhanced by complex encapsulation. In vitro digestion studies showed that the complex could pass through the gastrointestinal tract smoothly and effectively improve the bio-accessibility of quercetin. These findings provide a theoretical basis for the application of whey protein-based quercetin delivery systems in the functional food field.