Objective To explore the effect of bone allograft enbedded by vascularized thin cortex-periosteum flap for treatment of segmental bone defect.Methods The adult rabbit model of segmental tibial defect was established.The allograft de-antigenic rabbit tibia was designed and opened a window.Then the window was embedded by vascularized cortex-periosteum flap as a complex.Sixty healthy rabbits were randomly divided into 3 groups: experimental group,control group and blank group.In experimental group,the defect was repaired by complex,vascularized flap packing the allografts was used as the control group and only allografts was used as the blank group.X-ray examination,gross observation,histological observation and immunohistochemical examination were done on the bone and the surrounding tissues.Results In the experimental group,callus formation,transformation remodeling and neovascularization were observed.The vascularization,new bone formation and bone units mature were earlier in the experimental group than the control group.Conclusion Bone allograft enbedded by vascularized thin cortex-periosteum flap could reduce the time of bone repairment and has significant advantages compared to the directly packing model.