The repair of bone defects has been a major challenge to reconstructive surgery.Autologous grafts can gain satisfactory outcome in clinical treatment but with the significant disadvantages including donor site morbility and limited supply.Allotransplantation can result in the immunological rejection.Along the development of biomaterials and life sciences, the technique of tissue engineered bone (TEB) has been laboratorily and clinically proved an effective approach to generate bone tissue and repair bone defect in small and large animals.However, to have a more efficient and safe clinical application, there remain several bottlenecks to resolve.Firstly, we need to dertermine standardized parameters of hBMSCs, like which passage and how many of cells we seed to ensure the effectiveness and stability of TEB construction.Also,engineered bone formation are often incomplete in the reconstruction of large bone defects or for the poor recipient vascularity bed due to insufficient blood supply in the initial phase after implantation.Another problem is that the quality of BMSCs is affected by donor's age and health condition, we need to seek alternative cell source, like allogenic BMSCs, which allow pre-fabrication of TEB readily available for those patients who require a immediate transplantation.Lastly, we need a standardized protocol for a safe and efficient clinic application of TEB.In our lab, we have been systematically working on the dose-effect relationship between cell seeding quantity and in vivo bone yield, the quantitative comparisons of the osteogenesis and angiogenesis effects induced by different vascularization strategies for TEB, and the comparisons of the immunogenicity and repairing effects of allogeneic and autologous BMSCs based TEB for the critical-sized bone defect in large animals.Besides, we designed a general protocal for the clinical application of TEB.