In this work, the β-lactoglobulin/gum arabic (β-Lg-GA) complexes were prepared to encapsulate epigallocatechin gallate (EGCG), forming β-Lg-GA-EGCG complex nanoparticles with an average particle size of 133 nm. The β-Lg-GA complexes exhibited excellent encapsulation efficiency (84.5%), and the antioxidant performance of EGCG in vitro was improved after encapsulation. It was recorded that 86% of EGCG could be released in simulated intestinal fluid after 3 h of digestion, much faster than that in simulated gastric fluid, indicating that the β-Lg-GA complexes were effective in enhancing EGCG stability, which was confirmed using SDS-PAGE and SEM. Further spectrum results demonstrated that various intramolecular interactions including electrostatic, hydrophobic and hydrogen bonding interactions contribute to the formation of β-Lg-GA-EGCG complex nanoparticles. Also, XRDexperiments indicated that EGCG was successfully encapsulated by β-Lg-GA complexes. Therefore, the β-Lg-GA complexes hold great potentials in the protective delivery of sensitive bioactives.