To overcome the instability of sodium caseinate (NaCas) and zein binary nanoparticles in gastric digestion, and to improve the encapsulation of curcumin (Cur), hexaglycerol monooleate (HGMO) was employed as an anti-pepsin component to form ternary nanoparticles. The NaCas-Zein-HGMO nanoparticles were prepared using a self-assembly method that only required mixing at room temperature, and the optimal mass ratio for the components was determined to be 2:2:1. At a mass ratio of 1:20 between curcumin and zein, the NaCas-Zein-HGMO nanoparticles showed high encapsulation efficiency (91.18%) and provided effective chemical protection for curcumin. The Cur-NaCas-Zein-HGMO nanoparticles exhibited nanoscale dispersion, with a particle size about 236 nm, and demonstrated remarkable stability. In addition, the Cur-NaCas-Zein-HGMO nanoparticles exhibited improved resistance to simulated gastric fluid (SGF) digestion, increased antioxidant activity, sustained release profile, and exceptional rehydration capability. The results clearly showed that HGMO plays a crucial role in improving the physicochemical properties and encapsulation of curcumin of NaCas-Zein-HGMO nanoparticle. Hence, the novel ternary nanoparticles, NaCas-Zein-HGMO, have the potential to serve as an excellent delivery carrier for hydrophobic bioactive compounds, thereby mitigating their susceptibility to degradation by gastric digestion.