It is essential to design multifunctional biomaterials for pro-osteogenesis, rooting out residual tumor cells and resisting infection after surgical resection of bone tumors. Herein, niobium oxide with oxygen vacancy (NbOv) was synthesized through a deoxidation reaction, which exhibited photothermal property because of strong light absorption in near-infrared (NIR) region. Subsequently, magnesium‑phosphorus gel composite (MP) containing NbOv (MPNOv) was fabricated, which also possessed photothermal property that effectively ablated tumor cells and eradicated bacteria under NIR irradiation in vitro. The in vitro experiments confirmed that compared with MP, MPNOv significantly boosted bone mesenchymal stem cells responses (e.g., propagation and osteoblastic differentiation) due to the presence of NbOv with bioactivity. The in vivo experiments demonstrate that MPNOv fostered bone generation and prevented tumor recurrence as well as infection. In short, MPNOv with good biocompatibility and photothermal property as well as pro-osteogenesis served as a multiple functional biomaterial conquered the tri-challenges: bone defect, tumor recurrence, and bacterial infection in bone tumor therapy. Accordingly, as a novel photothermal therapeutic platform, MPNOv with tumor cells/bacteria-eradicating and pro-osteogenesis ability would be applicable for treatment of bone tumors.