Objective: Preparation of GYLEQ-Ca chelate with antioxidant activity and calcium supplement function. Methods: On the basis of solid-phase synthesis of GYLEQ antioxidant peptide, the conditions of chelation reaction between casein GYLEQ antioxidant peptide and Ca²⁺ were optimized by single factor and orthogonal experiment. The structure of GYLEQ-Ca chelate was characterized by IR and SEM. Meanwhile, the in vitro antioxidant activity, calcium retention in simulated gastrointestinal juice of GYLEQ-Ca chelate and its effect on cell viability were analyzed. Results: The optimum conditions for GYLEQ-Ca chelation reaction were temperature 50 ℃, time 40 min, pH 7.5, and peptide-calcium mass ratio 4∶1. The influence of chelation temperature on the chelation rate reached a very significant level, and the pH and peptide-calcium mass ratio reached a significant level. The infrared absorption peak of the GYLEQ-Ca chelate was changed compared with GYLEQ peptide, and the SEM observation showed that GYLEQ peptide was granular, while GYLEQ-Ca chelate was a network structure adhered together, indicating that GYLEQ peptide reacted with Ca²⁺ to form a new compound. The DPPH, hydroxyl radical scavenging rate and reducing power of GYLEQ-Ca chelate were higher than those of GYLEQ peptide. The calcium retention rate of GYLEQ-Ca chelate in simulated intestinal fluid was maintained at more than 70%, and GYLEQ-Ca chelate has no cytotoxicity. Conclusion: GYLEQ-Ca chelate has good antioxidant activity and calcium maintenance rate.