Abstract: The amorphous calcium phosphate (ACP) modified by gelatin was prepared with the coprecipitation method and then used as prototyping powder for three-dimensional printing (3DP). The 3DP products of bone repair materials were fabricated with deionized water serving as adhesive solution and then characterized with Fourier transform infrared spectroscopy(FT-IR), X-ray diffraction (XRD) and scanning electron microscope (SEM) separately. The mechanism of ACP stabilized with gelatin was initially discussed and the effect of gelatin content on the chemical stability of ACP and the compressive strength as well as porosity of 3DP products were investigated respectively. The optimal dosage of gelatin was determined to be 0.15% (mass fraction) and the corresponding compressive strength and bone conductibility of the 3DP products were 31.7 MPa and 30.2% respectively, at which a balance was obtained between them and the 3DP products could be widely used for repairing bone defects.