Abstract: Objective: To investigate the in vitro antioxidant activity and stability of white kidney bean antioxidant peptides (WKBAPs). Method: In order to analyze the effects of pH, temperature, metal ions, food ingredient composition, and simulated gastrointestinal digestion on the stability of antioxidant peptides in white kidney beans, the DPPH free radical scavenging rate, ABTS⁺ free radical scavenging rate, hydroxyl free radical scavenging rate, and total antioxidant capacity were measured. And an oxidative damage model was established in HepG2 cells induced by 2,2'-Azodiisobutyramidine dihydrochloride (AAPH) to explore the protective effect of WKBAPs on cellular oxidative damage. Results: Although the antioxidant activity of WKBAPs fluctuated under different processing conditions, the overall performance remained stable, still maintaining a high level of antioxidant activity. Only under strong acid, strong base, high temperatures (>60 ℃), high concentrations of Ca²⁺, Zn²⁺, Cu²⁺, and elevated levels of NaCl, citric acid, and glucose, the antioxidant activity of WKBAPs was significantly diminished (P<0.05). As the K⁺ concentration increased, the DPPH and ABTS⁺ radical scavenging capacities of WKBAPs initially decreased and subsequently stabilized. Meanwhile, the hydroxyl radical scavenging capacity and total antioxidant ability exhibited a slight but non-significant decline (P>0.05). During intestinal digestion, the DPPH and hydroxyl radical scavenging rates were significantly reduced, but the high antioxidant activity was still maintained. At the end of 240 minutes intestinal digestion process, its DPPH radical scavenging rate, ABTS⁺ radical scavenging rate, hydroxyl radical scavenging rate, and total antioxidant capacity were 78.03%±1.01%, 94.05%±0.47%, 74.75%±0.29%, and 0.76±0.02 mmol Fe²⁺/g, respectively. In the AAPH induced oxidative damage model of HepG2 cells, WKBAPs could increase the survival rate of HepG2 cells damaged by AAP oxidation. And it significantly reduced the production of reactive oxygen species (ROS), dramatically decreased the release level of LDH into the cell culture supernatant due to membrane damage, inhibited the production of malondialdehyde (MDA), and enhanced the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). Conclusion: WKBAPs has good in vitro antioxidant activity and stability, providing a theoretical basis for its application and development in the field of food and healthcare.