BACKGROUND:: Practical tests showed that the bone marrow mesenchymal stem cells (BMSCs) could proliferate and adhere on the surface of modifiednano-hydroxyapatite/poly (lactide-glycolide acid) (PLGA/g-HA) that demonstrated that the PLGA/g-HA had a good biocompatibility. OBJECTIVE:: To observe the effect of BMSCs combined with modified PLGA/g-HA on repair of rabbit radial bone defect. METHODS:: Model of 15 mm rabbit radial bone defect was established. The rabbits were randomly divided into three groups. The blank group was without any treatment, the experimental group was implanted with modified PLGA/g-HA + BMSCs, and the control group was treated with modified PLGA/g-HA. RESULTS AND CONCLUSION:: ①X-ray evaluation: The extent and speed of repair in the experimental group were obviously increased compared with the blank group and control group after 1-12 weeks of operation (P < 0.05). ②Histological observation: At 4 weeks, new formed bone could be seen, fibrous tissue extended into the space of scaffold, and bone lacuna was partially formed in the experimental group; At 8 weeks, new formed bone was increased and mature bone trabecula could be seen in the experimental group; Furthermore, at 12 weeks after operation, a great amount of mature osteoblasts could be seen, trabecular bone tightly packed, and the implants was gradually replaced by normal bone tissues in the experimental group. The experimental group showed its bone trabecula earlier than the blank group and control group. Tissue-engineered bone tissues constructed by BMSCs combined with modified PLGA/g-HA can promote the new bone formation of defect. The BMSCs combined with modified PLGA/g-HA are superior to the simple scaffolds.Tan YY, Shao Y, Li YX, Xu Y, Li C, Jin HJ, Zhang D. Modified nano-hydroxyapatite/poly (lactide-glycolide acid) combined with bone marrow mesenchymal stem cells for repair of rabbit radial bone defect. Zhongguo Zuzhi Gongcheng Yanjiu. 2012;16(21): 3843-3846. [http://www.crter.cn http://en.zglckf.com](Figure is included in full-text article.)