AIM: To investigate the effects of different doses of dexmedetomidine on stress and postoperative sleep in patients with coronary heart disease (CHD). METHODS: Sixty patients with coronary heart disease undergoing endoscopic abdominal surgery were randomly divided into three groups (n=20): low-dose group (D1), high-dose dexmedetomidine group (D2) and control group (C) In groups D1 and D2, a loading dose of dexmedetomidine (0.5 μg/kg) was injected with intravenous pump for 10 min, followed by the maintain dose of dexmedetomidine 0.2 and 0.6 μg·kg-1·h-1 until 30 min before the end of surgery, respectively. The control group was given equal volume of normal saline. The scores of AIS on the first day before operation, the first day after operation and the third day after surgery were recorded. The mean arterial pressure (MAP), heart rate (HR) and the dosage of propofol and remifentanil during the surgery were recorded before anesthesia induction (T0), immediately after tracheal intubation (T1), immediately after pneumoperitoneum injection (T2), and immediately after extubation (T3). RESULTS: The AIS scores of the three groups were significantly higher than those before operation (P<0.05). MAP and HR at T1, T2 and T3 in D1 and D2 group were significantly lower than those in C group (P<0.05), and HR at T3 in D2 group was significantly lower than that in D1 group (P<0.05). The dosage of remifentanil and propofol in group D2 was significantly lower than that in group C (P<0.05). Compared with group D1 and C, the incidence of severe bradycardia was increased (P<0.05). CONCLUSION: Different doses of dexmedetomidine can reduce stress, stabilize hemodynamics and improve postoperative sleep of patients with coronary heart disease during non-cardiac surgery.