The need for insulin in type 2 diabetes needs to be determined on a case-by-case basis. Insulin is needed for cases such as ineffective oral hypoglycemic drugs, serious complications, newly diagnosed type 2 diabetes with significant hyperglycemia, significant decrease in islet function in type 2 diabetes, and surgery. For obese patients with type 2 diabetes mellitus accompanied by insulin resistance, diet and exercise therapy can be used to control blood glucose in a reasonable range. Diet needs to reduce the intake of staple foods and sugary foods, strengthen physical exercise, and actively lose weight to control body weight. Oral hypoglycemic drugs are ineffective, there are serious complications, such as diabetic ketoacidosis, diabetic nephropathy, diabetic vasculopathy, etc., newly diagnosed type 2 diabetes mellitus with significant hyperglycemia, type 2 diabetes mellitus with significant hypoglycemia of the pancreatic islets, surgery and other cases, you need to take insulin to treat the disease. Diabetes mellitus is a chronic disease that can cause many complications, so it should be treated promptly after diagnosis to prevent further aggravation.