Abstract: In order to develop new calcium supplement products and improve the added value of peanut, the effects of different enzymatic hydrolysis methods on the chelation rate of peanut peptide-calcium chelate was studied. Chelation rate and calcium content were set as indexes, and the chelation process was optimized by response surface methodology on the basis of single factor test.The structure changes before and after chelation were analyzed by ultraviolet spectroscopy, infrared spectroscopy and thermogravimetric analysis.The results showed that compared with the other four proteases, alkaline protease was the best protease for hydrolyzing peanut protein. On the basis of alkaline protease as the main protease, flavor protease was complex on the basis of alkaline protease, and the complex ratio was 3:2. Then, the single enzyme hydrolysis rates of alkaline protease and flavor protease were compared.It was found that the addition of flavourase could improve the chelation rate of calcium, and the efficiency of the simultaneous enzymatic hydrolysis was significantly higher than that of the simultaneous enzymatic hydrolysis.The optimal conditions for the preparation of peanut peptide calcium chelate on the basis of two-enzyme step-by-step enzymatic hydrolysis were as follows:the mass ratio of peptide calcium 7.2:1, chelating pH 7.5, chelating time 50 min and chelating temperature 47℃. Under these conditions, the chelating rate reached 75.26%, which was close to the predicted value of the model, indicating that the parameters optimized by the model were effective and suitable for chelating reaction.UV spectrum analysis showed that peanut peptide reacted with aromatic amino acids after the coordination of peanut peptide with metal ions, which resulted in the change of hair chromogroup and the change of the position and intensity of the absorption peak due to the transition of electrons. It indicated that a new compound was formed after the chelation.Infrared spectrum analysis showed that compared with peanut peptide, the shift and intensity of the material characteristic peak of calcium peptide chelate were changed, indicating that the amino group and carboxyl group of the peptide were involved in the chelating reaction.The thermogravimetric analysis showed that the temperature of the calcium peptide chelate was significantly higher than that of the peanut peptide, indicating that the calcium peptide chelate might form a stable chemical bond. The decomposition of the chelate required more energy, indicating that the structure of the chelate was more stable.The results provided a theoretical basis for the development of new calcium preparation and the utilization of high value peanut meal.