C peptide and insulin are normal, the appearance of high blood glucose may be caused by insulin resistance. In many patients, C-peptide and insulin are secreted in equal molecular weight, which directly reflects the islet function of diabetic patients. For C peptide and insulin are normal, but the patient appeared blood glucose elevation, suggesting that the body may have resistance to insulin action, this situation is common in obese diabetes mellitus. For special diabetic patients, combined with hyperthyroidism, Cushing’s syndrome, etc., the body’s C-peptide and insulin levels are normal, but there is the presence of hormones that antagonize insulin, so high blood glucose may occur. It is recommended that patients with the above conditions should pay attention to weight control, dietary adjustments, and consult a doctor for consultation if necessary.