RESEARCH DESIGN AND METHODS Written informed consent was obtained from all subjects. Type 2 diabetic patients with bilateral critical limb ischemia (ankle-brachial index, ABI from 0.30 to 0.60) and at least with one foot ulcer, but without malignant tumor or gangrene above the ankle and/or severe coronary, cerebral and renal vascular disease, were eligible for the participation in this trial. Eligible patients took part in this study on a voluntary basis. They were randomized into the A and B group by use of a randomization table. One lower limb in A group or in B group was selected randomly for BMMSCs or BMMNCs transplantation as BMMSCs or BMMNCs group, the other lower limb in the same patient was selected for placebo（normal saline ,NS）injection as NS group. The whole procedures of this clinical trial were blinded to both patients and investigators.