1.Patients with type 1 diabetes require insulin therapy at the onset of the disease and need lifelong insulin replacement therapy. 2.Insulin therapy can be preferred for patients with new onset type 2 diabetes if they have obvious symptoms of hyperglycemia, occurrence of ketosis or ketoacidosis. The subsequent treatment plan will be determined according to the condition after the blood sugar is well controlled and the symptoms are significantly relieved. 3.Insulin therapy can be preferred when it is difficult to differentiate newly diagnosed diabetic patients from type 1 diabetes. After the blood sugar is well controlled, the symptoms are significantly relieved, and the typing is determined, the subsequent treatment plan will be formulated according to the typing and the specific condition. 4.Patients with type 2 diabetes can start the combined treatment of oral hypoglycemic agents and insulin if their blood sugar still does not reach the control target based on the combined treatment of lifestyle and oral hypoglycemic agents. Generally, when HbA1c>7.0% even after a larger dose of multiple oral medication combination therapy, insulin therapy can be considered to be started. 5. In the course of diabetes (including newly diagnosed type 2 diabetes), insulin therapy should be used as early as possible when there is significant weight loss without obvious causes. 6. Depending on the patient’s specific situation, basal insulin or premixed insulin can be used to start insulin therapy.