Empirical evidence proves that the antioxidant property plays a main role in the biological activities of biomaterials, which is influenced by several factors. In order to explore in‐depth, the influence of ionic systems on the antioxidant activity of collagen peptides was studied. Type‐I‐collagen peptides (GBB‐10SP and TYPE‐S) contained a high amount of hydrophobic amino acids and possessed good antioxidant activity at high concentrations in water. On the other hand, increasing [H+] and [Na+] concentrations (0.1 M to 0.5 M) decreased the reducing power of GBB‐10SP and TYPE‐S; however, [Ca2+] had no effect on the reducing power. Interestingly, the hydroxyl radical scavenging rate of these two peptides was increased by [Na+], decreased by [H+], and [Ca2+] had no effect. In general, TYPE‐S showed better antioxidant properties than GBB‐10SP. Overall, the above results confirmed that the antioxidant capacity of collagen peptides was affected by [H+] and [Na+] and not by [Ca2+].