The purpose of this study is to assess the safety and efficacy of umbilical cord blood mesenchymal stem cells with peripheral arterial disease.

The present study is designed to implant UCB-MSC in patients with CLI, which are resulted from peripheral arterial disease,such as thromboangiitis obliterans, atherosclerosis obliterans and diabetic foot, and to evaluate the safety and efficacy of the implantation procedure.

Inclusion Criteria:

1. Age of 18-75 years
2. Patients confirmed diagnosed peripheral vascular disease , ankle-brachial index < 0.9
3. Poor distal arterial outflow tract
4. Patient had at least 3 months conservative treatment ,which resulted in little or no improvement
5. Poor physical condition can not tolerate surgery
6. Patients are willing to participate in the study and sign the informed consent.

Exclusion Criteria:

1. Renal function damage (over 2 X upper normal range) Liver function damage (over 3 X upper normal range )
2. Severe or acute organ damage
3. Presence of malignancy
4. Pregnancy or lactating patients
5. HIV positive
6. ABI≧0.9
7. A history of severe allergies related cell therapy
8. Conservative treatment < 3 months
9. Acute limb ischemia
10. Local obvious infection uncontrolled
11. Alcoholics or drug abusers within a year
12. Severe psychiatric disorder.
13. Patients need surgical treatment
14. Above the ankle gangrene
15. Patients with other factors which were considered not to be suitable to participate in the study by the investigators.