Abstract： Objective To compare vascularization osteogenesis and membrane-induced osteogenesis in bone defect repair with fascia flap at distinct periods,and to offer reference for clinical intervention of bone defect.Methods Non-cellular tissue engineering bone was constructed using osteogenesis absorption material (OAM) containing recombinant human bone morphogenetic protein 2 (BMP-2) and rabbit bone marrow stem cells (BMSCs),and the prepared rabbit ulnar defect model (n=75) was repaired with tissue engineering bone transplantation.Rabbits were divided into 3 groups.In group A (n=25),simple tissue engineering bone implantation was performed; A fascia flap with pedicle was prepared in the bone defect neighbouring region,the tissue engineering bone with pedicle-free fascia flap was implanted in group B (n=25),while the tissue engineering bone with pedicle fascia flap was transplanted in group C (n=25).Detection of the absorption ratio in osteogenesis region and empty region,bone quantitative morphology analysis,and vascular image quantitative analysis was carried out at week 4,8,12 and 16 after surgical operation.In addition,radionuclide bone imaging examination was performed,and ink was injected into axillary artery at 8,12 and 16 weeks after operation for observing vascular regeneration in repairment region.Results As compared with group A and B,the absorption ratio of osteogenesis region and empty region,proportion of newly-formed bone trabeculae area and microscopic bone repairment region,the area of vascularization per unit as well as the absorption ratio of region of interest (ROI)during radionuclide bone imaging increased significantly(all P＜0.05) in group C at week 4 and 8 after operation.As compared with week 8,there was an increase in absorption ratio of osteogenesis region and empty region as well as the proportion of newly-formed bone trabeculae region and microscopic repairment region (all P＜0.05)at week 16 in all groups.At week 8 after operation,the vascularization area per unit in repairment region was (7.20±0.23) ％,(7.75±0.57) ％ and ( 24.75± 1.58 ) ％ in group A,B and C,respectively; absorption ratio of ROI during radionuclide bone imaging was (7.17±0.01)％,(10.12±0.02)％ and (29.37±0.04)％,respectively.At week 16 after operation,the vascularization area per unit in repairment region was (4.31±0.13 )％,(4.69±0.12) ％ and (9.98±0.74)％ in group A,B and C,respectively; absorption ratio of ROI during radionuclide bone imaging was (5.03±0.01)％,(5.16±0.04)％ and (12.75±0.03)％,respectively.Within-group comparison revealed a reduction in the vascularization area per unit in repairment region as well as absorption ratio of ROI during radionuclide bone imaging(all P＜0.05).Conclusion Vascularization osteogenesis dominates the early stage,while membrane-induced osteogenesis is dominant in the late phase of fascia flap with pedicle repair.