There is no clear data on how long a person can live with diabetes. If the baseline condition is good, the treatment is timely, and the blood glucose control is stable, the life expectancy is generally not affected; however, if the blood glucose control is not satisfactory, ketoacidosis, diabetic nephropathy and other complications may occur, which will affect the life expectancy to varying degrees. If a diabetic patient has a good baseline condition, no serious other systemic diseases, diabetes is detected in time, treated as early as possible, and blood glucose is regulated through a combination of diet, exercise, and medication to keep blood glucose within the target range, the patient’s life expectancy will generally not be affected. If diabetes is not detected in time and blood glucose control is not satisfactory, a variety of complications may occur, such as ketoacidosis, lactic acidosis and other acute complications, as well as diabetic nephropathy, diabetic retinopathy and other chronic complications, especially type 2 diabetes mellitus with an insidious onset of early onset of diabetes mellitus may have already occurred at the time of diagnosis of diabetes mellitus complications. After the diagnosis of diabetes mellitus, it is necessary to standardize the treatment under the guidance of a professional doctor, to control the blood glucose at the ideal level, and to monitor the blood glucose on a regular basis.