Preparation of peptides chelated calcium from silkworm pupa peptides, taking the soluble calcium content as the main index, and considering the chelation and yield rate, the effects of reaction pH, temperature, time, and peptide-calcium ratio were examined. On the basis of single factor experiment, Box-Behnken central composite design was utilized, and the optimal conditions were as followed: reaction time 80 min, reaction temperature 73 ℃, pH 10, peptide calcium ratio 3.41.0. Under this condition, the soluble calcium content of the silkworm pupa peptide chelated calcium was 14.51%. Through the UV absorption and infrared spectroscopy and SEM analysis, it showed that the silkworm pupa peptides and calcium ions chelation occurred, and the phosphate group, carboxyl group and amino group participated in the reaction.