Applying insulin appropriately under a doctor’s supervision does not usually affect a patient’s life expectancy; it is the various complications of diabetes that may affect a patient’s life expectancy. Good control of blood glucose levels by insulin in diabetic patients usually does not affect life expectancy, and there is no question of how long one can live on insulin. Acute complications such as diabetic ketoacidosis and hyperosmolar hyperglycemic syndrome can even result in short-term death of the patient if not treated promptly. Various chronic complications such as diabetic nephropathy, diabetic retinopathy, etc., also need to be actively treated, such as diabetic nephropathy may require dialysis in the late stage, if not dialysis machine body metabolic wastes can not be eliminated, but also affects the patient’s life. It is recommended that patients follow the doctor’s instructions to apply insulin, the occurrence of uncomfortable symptoms, timely medical care.