Osteosarcoma treatment requires surgical resection, but residual tumor cells and bone defects remain major challenges. We developed a 3D-printed hydrogel scaffold integrating photothermal therapeutic and osteoinductive functions. Gelatin-based solution formed a biocompatible hydrogel matrix, while dopamine was modified to enable composite network formation, enhancing mechanical flexibility through catechol-mediated interactions. MXene nanosheets provided conductivity and near-infrared responsiveness for photothermal therapy (PTT), enabling ablation of residual osteosarcoma cells and bacterial infection. DNA molecules were incorporated to promote osteogenic differentiation, angiogenesis, and inflammatory modulation. In vitro and in vivo studies showed enhanced osteogenic marker expression, bone regeneration, and osteosarcoma cell apoptosis after PTT. This multifunctional scaffold offers a promising platform for post-surgical bone defect repair while preventing tumor recurrence.