In this study, borosilicate bio-glass (BG) was incorporated into magnesium phosphate cement (MPC) for the purpose of developing an injectable and bioactive composite cement with suitable physicochemical and biocompatible performance. Results show that the BG-incorporated MPC possesses an excellent injectability, and can be used to fill in different 3D printed defect models using a syringe with a moderate setting time. Meanwhile, BG can retard the setting time and adjust the exothermic temperature of MPC. When the MPC/BG ratio was 3:1 (MPC3-BG), its corresponding setting time, peak temperature, anti-washout ratio and compressive strength were 9.9 ± 0.7 min, 45.8 ± 1.6 °C, 87%–90% and 13.5 MPa, respectively, which were suitable for injection and bone reparation. Characterizations of MPC3-BG showed that it had a faster degradation rate than MPC and the functional ions of boron and silicon could be released from the dissolution of the composite cement. In vitro and in vivo experiments also demonstrated that MPC3-BG had a stimulatory effect on the cell proliferation and new bone regeneration.