The defatted soybean meal was hydrolysised by alcalase to explore the optimal preparation parameters of calciumchelated soybean peptides, and the properties of alciumchelated soybean peptides were analyzed. The effects of mass ratio of peptide and calcium, chelating temperature, pH and chelating time on calcium binding capacity were studied, and the chelating process was optimized by Box-Benhnken experimental design and response surface methodology (RSM). The results showed that the optimum chelating conditions were as follows: ratio of peptide to calcium was 16, chelating temperature was 38℃, chelating time was 44min, and pH value was 66. Under the optimal conditions, the calcium content was the highest (7873mg/g) in calciumchelated soybean peptides. Moreover, it was concluded that the solubility of the finally obtained calciumchelated soybean peptides was 9859%. Furthermore, the molecular mass distribution of soybean peptidecalcium chelate was also determined by highperformance liquid chromatography (HPLC). The proportion of peptides with a relative molecular weight higher than 5000Da was 176%, peptides with a relative molecular weight lower than 5000Da accounted for 9824%, and peptides with molecular weight lower than 1000Da accounted for 8024%. Among them, the peptides with the relative molecular weight of 180~500Da accounted for the largest proportion. It provided a new method for the research and development of new soybean nutrition and synthesis of new calcium supplements.