Osteosarcoma is one of the most aggressive cancers which greatly threatens the health of adolescents and surgery is difficult to resect the whole piece of tumor tissue. The residual tumor cells might proliferate at the tumor site and invade into the blood circulation, leading to tumor recurrence and metastasis. Besides, the invasion of tumor cells could also lead to bone injury. We designed a recombinant fibronectin-cadherin fusion protein/hydrophobically modified glycol chitosan-PTX nanoparticles (rFN-CDH/HGC-PTX) layer-by-layer self-assembly polymer based on biphasic calcium phosphate ceramic (BCP) (BCP-PEI-(rFN/CDH-PTX/HGC)n-rFN/CDH). The SEM, FTIR, XPS and contact angle experiments proved the successful synthesis of the polymer. The chemotherapy drug PTX and bone-repairing-related rFN/CDH fusion protein could be stably released within one week and the in vitro experiments exhibited the efficacy of the polymer to kill residual tumor cells and promote the proliferation of osteoblast, confirming that our polymer was a superior material for postoperative osteosarcoma therapy.