The calcium-binding activity of tilapia scale protein hydrolysates sequentially hydrolyzed by trypsin, flavor enzyme and pepsin were investigated. The hydrolysates were divided into four fractions using G-15 gel chromatography, and the F3 fraction has the higher calcium-binding activity of 196.3 mg/g. The UV-vis and the Fourier transform infrared spectroscopy (FTIR) demonstrate that the amino nitrogen atoms and the oxygen atoms belonging to the carboxylate groups are the primary binding sites for Ca2+. The X-ray diffraction and scanning electron microscopy (SEM) confirmed the reaction between the peptde and calcium. The results obtained indicated that this fish scale protein hydroly-sates have potential as functional foods for calcium-supplementation.