The life expectancy of a diabetic patient is related to the type of diabetes, the patient’s age, the presence of complications, etc. It is not essentially related to long-term insulin injection, and should be analyzed specifically according to the patient’s condition, and should not be generalized. Insulin injection is to promote insulin secretion in the body, which can effectively control blood sugar. In the case of type 1 diabetes, insulin injection may be required for life, and if the condition is effectively controlled, the life expectancy is no different from that of ordinary people. For young patients with good blood sugar control, no complications and good compliance with treatment, life expectancy is no different from that of normal people. Older patients with poor blood glucose control and serious diabetic complications, such as diabetic hyperosmolar coma and ketoacidosis, can threaten patients’ lives for a short time and even lead to death. It is recommended that patients with long-term insulin injections regularly test their blood glucose, take medications for adjunctive treatment and strengthen their resistance.