Diabetic foot is a painful, ulcerative and gangrenous lesion of the foot caused by lower extremity vascular disease – atherosclerosis, diabetic neuropathy, peripheral small artery occlusive disease due to peripheral nerve sensory impairment and vegetative nerve damage, or cutaneous microangiopathy and bacterial infection. It is often due to the synergistic effect of three factors: ischemia, neuropathy and infection. Due to arteriosclerosis of the lower extremities, vascular narrowing or occlusion, coupled with the weakening of vasomotion due to vegetative neuropathy, resulting in inadequate blood supply to the foot, local tissue ischemia and decreased resistance to infection, when the foot is improperly treated for minor trauma, such as ill-fitting shoes extrusion, abrasions, chaps or corns, can cause the formation of ulcers on the infected surface, and because the patient’s pain sensation is reduced or disappears, the lesion cannot be detected in time, often making the ulcer larger. Due to the sensory impairment, contact with hot objects do not know to avoid, but also can cause burns. Lower limb vascular lesions cause ischemia and hypoxia, resulting in foot pain and intermittent broken walking due to foot pain when walking. Ischemia of the lower extremity is aggravated after bed rest, while causing pain during body rest, which is manifested as resting. On examination, it can be found that the dorsal foot and posterior tibial artery pulsation is weakened or disappeared, local skin malnutrition, skin temperature is reduced, color is abnormal, pale when the affected limb is elevated, drooping is purplish, and the foot is prone to chronic ulceration. When limb ischemia is severe, foot gangrene, or tissue necrosis, can occur. The gangrene is black in color, with the toes and heel as the preferred sites, and gradually progresses upward after the onset of gangrene. Gangrene can develop suddenly and with severe pain. Some patients may also have painful neuropathy, and the necrotic tissue is susceptible to bacterial infection, which can be foul-smelling when accompanied by anaerobic infection, i.e., wet gangrene. When a diabetic foot is present, it can be graded into 6 grades according to the following criteria. grade 0: no open lesions, but on examination there are obvious signs of inadequate blood supply, such as a markedly weakened dorsalis pedis artery pulsation; grade 1: superficial ulcers, which can be caused by water scars or other injuries, or arise spontaneously; grade 2: ulcer formation, deep to the muscle glare, ligaments, and bone joints; grade 3: deep ulcer infection with osteomyelitis and pus ulcer sinus tract formation; grade 4: with toe and/or partial foot gangrene; Grade 5: gangrene of the entire leg, usually requiring amputation. Therefore, diabetic patients need to take good care of their feet, quit smoking, control blood sugar, control blood pressure, regulate blood lipids, wear loose and soft shoes, properly treat foot abrasions, chafing or corns, etc. When intermittent claudication and resting pain occur in the lower limb vascular lesions, please seek medical attention in a timely and appropriate manner to deal with the vascular lesions and improve blood circulation in the lower limbs and feet, which can avoid amputation or reduce the plane of amputation.