Objective To study the effect of transplantation of bone marrow mesenchyml stem cells on diabetic rats.Methods The diabetic rat model was induced with a single intraperitoneal injection of streptozotocin.The diabetic rats were divided into two groups,control group and transplanted group.The control group was intraperitoneal injected same volume culture medium.The transplanted group was directly injected the bone marrow mesenchyml stem cells into pancreas.The blood glucose level was evaluated.Results After transplantation blood glucose level in diabetic rats was decreased significantly from 17.58±2.46 mmol/L to 5.94±2.25 mmol/L(P0.01).The blood glucose level between the control group and the transplanted group was significantly(P0.01).Conclusion The diabetic rats blood glucose level is lowered by bone marrow mesenchyml stem cell trnsplanttion.