Type 2 diabetic patients with diabetic foot were enrolled and randomized to either transplanted group or control group. Patients in transplanted group received the stem cells treatment,Patients in control group received the standard treatment. After culture in vitro, umbilical cord mesenchymal stem cells should go through safety evaluation which include culture and check of pathogenic microorganisms (bacteria, mycoplasma, chlamydia, eumycete and viruses) of the cells medium and karyotype analysis of the mesenchymal stem cells. Only the safe cells were harvested and transplanted by multiple intramuscular injections into the impaired lower limbs. Follow-up index include: efficacy (pain,ulcer healing rate, lower limb amputation rate and ,ankle-brachial index,magnetic resonance angiography,electromyogram) and safety (infection of the injection site, fever, and tumour generation).