Objective To evaluate the efficiency of xenogenic deproteinized bone (DPB) based on cortical bone-derived osteoblasts as an alternative in repair of critical bone defect.Methods A total of 36 Newzealand rabbits were randomly divided into groups A,B and C.Critical bone defect with a length of 1.5 cm was created in one side of the radius.The defect was filled with a DPB scaffold seeded with osteoblasts (group A),autograft (group B) and DPB scaffold (group C).All specimens were selected for X-ray examination,bone mineral density (BMD) measurements,gross samples observation,biomechanical test and histological observation at 12th week postoperation.Results X-ray examination displayed that the radial defect which was still obvious in group C disappeared in groups A and B.BMD measurements showed that there was no significant difference in BMD between groups A and B,but that was higher in group C (P < 0.05).Gross samples observation revealed that the radial defect which was still obvious in group C disappeared in groups A and B.Biomechanical testing demonstrated that the maximum bend load in groups A and B was significantly higher than in group C (P < O.05 ).Histologically,there was abundant of newly bone formation in group A,the medullary cavity recanalized in group B,and a small amount of newly bone formation in group C.Conclusion Radial critical bone defect could be repaired efficiently by xenogenic DPB based on cortical bone-derived osteoblasts. Key words: Osteoblasts; Deproteinized bone; Bone defect