The management of osteosarcoma presents a significant challenge, and the creation of an intelligent synergistic drug delivery system is broadly acknowledged as a promising approach to therapy. Hence, in this study, a temperature-sensitive hydrogel containing DOX-loaded and folic acid-modified BPNSs that can be injected was developed to enable drug release via a pH/NIR response, aimed at synergistic photothermal‒chemotherapeutic treatment of osteosarcoma. The active targeting of BPNSs-PEG-FA/DOX involved liquid-phase stripping and electrostatic adsorption, leading to the preparation of the BPNSs-PEG-FA/DOX aqueous dispersion hybrid hydrogel matrix as a BPNSs-PEG-FA/DOX@Hydrogel through a cold method. This composite hydrogel exhibits favorable through-needle properties, superior photothermal conversion efficiency, pH/NIR intelligent responsiveness, and controlled delayed-release drug release capabilities, along with favorable in vitro cellular biocompatibility. It also demonstrates effective in vitro and in vivo active targeting, controlled delayed release, and synergistic photothermal-chemotherapeutic anti-osteosarcoma activity, showing considerable promise for the treatment of superficial tumors such as osteosarcoma.