Diabetic patients with low blood glucose in the afternoon and high blood glucose in the morning may be the dawn phenomenon, Sumuje phenomenon. Dawn phenomenon should increase the dosage of nighttime insulin, and Sumuje phenomenon should reduce the dosage of bedtime insulin. Dawn phenomenon refers to diabetic patients with better glycemic control at night without hypoglycemia. Early morning leads to a short period of elevated blood glucose due to increased secretion of growth hormone and cortisol. Therefore dawn phenomenon should increase the dosage of insulin at night. Sumuje phenomenon is a multiple blood glucose measurement at night found to have hypoglycemia, and fasting blood glucose measurement in the morning is high. Generally, it is a rebound hyperglycemia caused by the increase of glucagon in the body due to hypoglycemia. Therefore, insulin dosage at bedtime should be appropriately reduced. It is recommended that diabetic patients with dawn phenomenon or Sumujie phenomenon should go to the hospital in time for targeted treatment under the guidance of the doctor, so as to avoid delaying the condition and triggering adverse consequences.