Objective To observe effects of the core binding factor α1 (Cbfα1) in its promoting differentiation of the rabbit marrow mesenchym al stem cells (MSCs) into osteoblasts. Methods The rabbit marrow MSCs were isolated and cult ured in vitro and were divided into 3 groups. In the control group, the marr ow MSCs were cultured by DMEM; in the single inducement group, they were cultured by the condition medium (DMEM, 10% fetal bovine serum, dexamethasone 10 mmol/L, vitamin C 50 mg/L, and βGP 10 mmol/L); and in the experimental group , the ywere transfected with AdEasy1/Cbfα1,and then were cultured by the condition m edium. The alkaline phosphatase(ALP) activity and the experission of osteocalcin as the osteoblast markers were measured with the chemohistological and immunohi stochemical methods at 3 days，1，2，3，and 4 weeks after inducement. Results More than 90% MSCs were grown well in vitro. The GFP was positive in MSCs after their being transfectived with AdEasy1/Cbfα1. The ALP activity and the experission of osteocalcin were significantly upregulated in the transfection group compared with those in the single inducement group and the control group at 1, 2, 3, and 4 weeks （Plt;0.05）.The mineralized node began to appear at 2 weeks in the experiment al group and the single induction group, but did not appear in control group. Conclusion Cbfα1 can obviously promote differentiation of the rabb it marrow mesenchymal stem cells into the osteoblasts.