Bone tissue engineering based on 3D printing bone scaffolds is a potential bone repair strategy. The composite powders of phytic acid chelating modified hydroxyapatite (IP6-HA), β-tricalcium phosphate (β-TCP) and anhydrous calcium dihydrogen phosphate (MCPA) with different molar ratios were used as solid phase, and the aqueous solution with different propylene glycol (glycerine) content was used as liquid phase. By adjusting IP6-HA powder content in composite powders and glycerine content in the curing solution, the calcium phosphate composite slurries of brushite system that can be applied to the room-temperature extrusion 3D printing bone scaffolds were prepared. The results show that hydration products of the composite slurries are mainly hydroxyapatite (HA), β-TCP and anhydrous calcium hydrogen phosphate (DCPA). When the glycerine content in the curing solution is 50% (mass fraction), the composite slurries exhibit excellent printability and mechanical properties, and the compressive strength can reach up to 19.8 MPa. The presence of residual IP6-HA changes the mineralization structure of apatite on surface of the solidified samples and improves the mineralization ability. The prepared scaffolds have a complete structure and uniform pores, and the compressive strength can reach 5.8 MPa. The composite slurries prepared in this study can be used to prepare bone scaffolds by room-temperature extrusion 3D printing technology, and has a good application prospect in the field of 3D printing bone scaffolds.