The peptide ferrous chelate was prepared using tilapia scale collagen peptide and ferrous chloride salt as raw materials, and its optimal chelating conditions and chelate structure were investigated. Using chelate yield as an indicator, the chelation conditions were optimized by single factor and response surface methods; The structure and amino acid composition of the chelate were analyzed by scanning electron microscope, Fourier infrared spectroscopy, X-ray diffraction and amino acid analysis. The results showed that the optimal reaction conditions for preparing the chelate were pH 5.30, peptide concentration 3.00%, and peptide to iron mass ratio 3.2∶1.0. Under these conditions, the chelation rate was 82% and the chelate yield 65.43%; The analysis of amino acid composition showed that the amino acid composition accorded with the composition characteristics of collagen polypeptide, and the content of aspartic acid, glutamic acid, lysine, histidine and arginine increased after chelation; Diffraction and other results showed that the peptide and ferrous salt were combined by a coordination bond to form a peptide ferrous chelate.