Abstract: In order to develop a new type of calcium supplements and broaden the application field of wheat protein peptides, the preparation process of peptide-chelated calcium from wheat protein was explored and structural characterization was conducted. Using wheat protein as raw material and calcium chloride as calcium source, the hydrolysis effects of five common commercial enzymes and thermal protease PC 10F and the chelating effects of active peptides on calcium ions were compared. The preparation process was preliminarily studied by single factor test, and then further optimized by orthogonal test. The structure of the chelate was characterized by scanning electron microscopy, ultraviolet spectroscopy, and particle size potential. It was found that under the condition of 6% hydrolysis degree, the peptides produced by thermal protease PC 10F had the best chelating effect on calcium ions. The optimal process parameters were obtained when the reaction temperature was 50 ℃, the mass ratio of polypeptide to calcium chloride was 3∶1, the reaction time length was 50 min, and the reaction system pH value was 7. The binding amount of calcium with the chelates can reach higher than 60 mg/g. The chelating of wheat protein polypeptide and CaCl₂ did occur, and a new substance was produced. After chelating, the internal molecules of the substance attracted to each other and aggregated, resulting in a more dense structure. The polypeptide and calcium ion coordinated to form a ring structure, resulting in a smaller size and a more stable state of the chelate. The wheat polypeptide chelated calcium obtained by the research has low production cost, simple process and practical application value.