Diabetes is associated with many severe complications, such as heart disease and nerve damage. Diabetics have elevated blood glucose levels that result in peripheral neuropathy. As a result, diabetics always feel painful about their lower limbs and may need to have lower limb amputation. The diabetic foot ulcers are hard to heal and require extensive medical treatments and follow ups. The purpose of this study was to evaluate the effect of infrared radiation therapy using a heating pad with carbon fibers (LinkWin Technology Co., Taiwan) on the diabetic foot. Ten diabetics and 4 non-diabetics were recruited for this study. The participants were assessed for their microvascular function before and after the interventions in each month for three consecutive months. The results showed that surface temperature increase by 2° after using the pad in the first and third months (p < 0.05); and blood flow increase on the plantar foot (p < 0.05) but not on the dorsal foot. The increase in blood flow may alleviate diabetic-related complications. The results of autonomic nervous testing indicated that the activity of sympathetic nervous increased after using the pad. In conclusion, the use of heating pad with far infrared radiation could improve blood flow and autonomic nervous system in diabetics, therefore improving alleviating symptoms of diabetes-related complications.