[Objective]To investigate the efficacy of platelet-rich plasma ( PRP ) combined with free bone block particulate replantation in the treatment of open tibial defect. [Methods]From February 2019 to February 2021, 15 patients with open tibial bone defect were treated. The tibia was fixed by one-stage debridement and external fixation, and the free bone mass was fostered between the mid thigh rectus femoris and the lateral thigh muscle on the same side. The external fixation was removed in the second stage after wound healing, and the fracture was fixed with steel plate. The foster bone mass was bitten into particulates by a bone bite forceps, and then mixed with platelet-rich plasma ( PRP ) to implant in the bone defect. Postoperative regular follow-up. [Results]15 patients were followed up. The follow-up time was 12 ~ 24 months. There was no infection after operation. All fractures healed smoothly. The healing time was 10 ~ 15 months, with an average of 12.1 months. [Conclusion]PRP combined with free bone block particulate replantation in the treatment of open tibial defect avoids rejection of allogeneic bone transplantation, donor site damage of autologous bone transplantation, microscopic technology of vascularized bone transplantation and matching requirements. It is a simple and effective method for the treatment of open bone defect with the advantages of simple operation and reliable curative effect.