Diabetic patients often suffer from long-term disorders of blood glucose and lipid metabolism, which can easily lead to damage of vascular endothelial cells and basement membrane, resulting in diabetic vascular complications.DM patients present with combined neuropathy and varying degrees of vascular disease resulting in lower limb infection, ulcer formation and/or deep tissue destruction called diabetic foot. It is highly disabling and lethal, with a high amputation rate of more than 20%, often ending in amputation and death. Auxiliary examination Body fluid and tissue examination 1.Blood routine and blood sedimentation examination: it can understand the patient’s white blood cell level and neutrophil ratio, determine whether there is infection and the effect of treating infection. 2.Ulcer secretion culture and drug sensitivity test: It helps to understand the category of pathogenic bacteria and optimize antibiotic treatment. 3.Tissue biopsy: It is very important during ulcer treatment, not only to obtain information about deep lesions, but also to release bony compression. Imaging examinations 1. X-ray: x-ray orthopantomographs can help to understand the presence of bone destruction and the coexistence of Charcot’s arthropathy. However, the false-negative rate of x-ray is higher in the early stage of ulceration that affects the bone. 2. CT examination: It can provide a more detailed understanding of the degree of bone destruction, the extent and the degree of concomitant Charcot arthropathy, and the typing. To guide the follow-up treatment. 3.MRI: This examination is generally necessary to understand the location and extent of deep abscesses in the foot and the extent of ulcer spread (such as the extent of spread of ulcers and abscesses along the flexor tendon sheath to the proximal end) when deep infection cannot be determined. In addition it helps in the diagnosis of bone infection. Peripheral vascular examination 1. Palpation of the dorsalis pedis artery and posterior tibial artery pulsations to understand large vascular lesions in the foot is a simple, traditional and clinically valuable examination method. The disappearance of these arterial pulsations often indicates that the patient has a serious lesion and requires close monitoring or further examination, such as checking Doppler manometry. 2.Ankle-brachial index, i.e., ankle artery-brachial artery blood pressure ratio (ABI): By measuring the blood pressure in different planes of the limb, the degree of arterial patency and the site of stenosis or obstruction can be determined, which is a very valuable indicator of the vascular status of the lower limbs.