Abstract： Objective To study the effect of fascial flap with membrane -induced bone repair on rabbit ulna defect with hyperbaric oxygen as an accessory treatment,and to provide the basis for further clinical application. Methods An animal model of bone defect in the left ulnar bone of the adult New Zealand rabbits was established. Autogenetic red bone marrow was taken and mixed with bone -induced active material containing BMP to form a noncellular tissue engineering complex. Then,through microsurgery,an innominatal fascial flap with vessels belonging to a capillary network was prepared,and had the tissue engineering complex wrapped up and the bone defect filled up. After surgery,the rabbits were randomly divided into two groups: the experimental group ( Group A) and the control group (Group B),each having 12 animals. The rabbits in Group A breathed normal air while those in Group B were given hyperbaric oxygen treatment. Radiography (X-ray),macroscopic observation,histological examination,dosimetric analysis of bone shape in the prosthetic area and also analysis of vascular image in the junctional area were performed some time later. Results From X-ray films,macroscopic observation,histological examination,marked statistical differences could be seen not only in the aspects of the growth of blood vessels in the implant and the rate and quantity of bone trabecula and cartilage tissue formation,but also in the aspects of the development of mature bone structure,the remolding of shaft structure,the reopening of marrow cavity,the absorbance and degradation of the implant,as well as morphological changes in the prosthetic area,between the two groups at the same time point within the same period (P ＜0.05). Experiments showed that Group B was superior to Group A in the capability of ossification in vivo and the effect on the recovery of bone defect. Statistical analysis indicated that significant differences could be noted in the quantity and quality of blood vessels per unit area at the same time point within the same period (P＜0.05) between the two groups through dynamic measurement with the vessel image analyzer in the junctional area. The fact that Group B was superior to Group A might be an indication that HBO could enhance the vascularization of the newly -formed engineered bone. Conclusions Fascial flap with membrane- induced bone repair of rabbit ulna defect with hyperbaric oxygen as an accessory treatment seemed to have dual effects of membrane. - induced bone regeneration and vascularization and had significant effects on the quantity and quality of ossification.