Objective:Alkaline electrolyzed water (AEW) produced by drinking water electrolysis with three different negative REDOX potential values was used to study its physical and chemical properties, antioxidant and gastric acid relieving capacity.Methods:The pH value, oxidation-reduction potential (ORP), total dissolved solids (TDS) and mineral content of AEW were determined, and the free radical scavenging rate and anti-lipid peroxidation ability of AEW were studied by spectrophotometry. The acid capacity of different water samples in vitro was studied by artificial gastric model.Results:The negative ORP value of AEW is positively correlated with the pH value (P＜0.01). The scavenging rates of superoxide anion, hydroxyl radical, ABTS+ and anti-lipid peroxidation of alkaline electrolyzed water were significantly different from those of tap water (P＜0.05), and the antioxidant capacity of AEW was positively correlated with the negative ORP value (P＜0.01). The neutralization ability of AEW to artificial gastric acid in vitro was significantly different from that of tap water (P＜0.05), and tap water has a certain dilution effect on gastric acid.Conclusion:AEW with different negative ORP value produced by electrolysis of tap water has antioxidant activity, which gradually increases with the increase of negative ORP value, and has the ability to relieve gastric acid excess, with equivalent effect of 0.2% NaHCO3.