Hyperglycemia caused by stress is commonly seen during perioperative period, which is closely related to infection, death and other postoperative complications. Therefore, it is necessary to pay attention to stress-induced hyperglycemia and the modulation of blood glucose concentrations. This paper discusses the effects of dexmedetomidine on perioperative stress response and insulin secretion and eventually the blood glucose level. Dexmedetomidine is a highly selective α2 adrenergic receptor agonist that can inhibit stress and lower blood glucose. Meanwhile, it can also directly activate α2 adrenergic receptors on the pancreatic β-cells to reduce insulin secretion and increase blood glucose level. The effects of dexmedetomidine on blood glucose are needed to be further explored.