Obese type 2 diabetes is only a relative lack of insulin, because an important factor in its development is obesity, obesity when the body’s use of insulin significantly reduced (the so-called insulin resistance), resulting in a large amount of insulin secretion in the body, weight in their own high insulin situation significantly increased, and weight gain and higher demand for insulin, hyperinsulinemia and body obesity on the formation of a vicious circle, until the pancreatic insulin secretion capacity can not compensate for the body’s increasing insulin demand. Until the insulin secretion capacity of the pancreas is unable to compensate for the increasing insulin demand of the body. Usually, when a type 2 diabetic is diagnosed, the patient’s islet function has usually declined to 50% of its peak, and thereafter the islet function will decline to a certain extent every year, and within 10 years many people will decline to less than 20%, at which time some patients cannot achieve ideal blood glucose control by using oral hypoglycemic drugs alone, and need to add insulin to control blood glucose. But not all type 2 diabetes is applicable. The more appropriate treatment for obese patients with type 2 diabetes should be the first choice of drugs that increase insulin sensitivity, such as metformin and glitazones. Insulin should be used with caution in the following cases: type 2 diabetic patients with poor diet control and severe overweight, patients who are prone to hypoglycemia (such as liver disease or severe gastrointestinal disease), and patients whose blood sugar can be ideally controlled with oral hypoglycemic drugs and who have no contraindications to taking oral hypoglycemic drugs. It should be noted that cautious use does not mean no use, but under the guidance of a doctor, mastering the conditions of use at the right time, in the right amount and in the right degree.