OBJECTIVE： To investigate the cardiac-protective effects and safety of dexmedetomidine on cardiac muscle of elderly patients with non-coronary artery bypass grafting （OPCABG）. METHODS： 50 elderly patients underwent OPCABG were selected and randomly divided into observation group and control group， with 25 cases in each group. Both groups received morphine 0.2 mg/kg+scopolamine 0.3 mg/kg intramuscularly 30 min before operation， and were given sulfentanyl 1 μg/kg+etomidate 0.1-0.2 mg/kg+pipecurium bromide 0.1 mg/kg for anesthesia induction. Observation group was given Dexmedetomine hydrochloride injection 1 μg/kg，ivgtt，within 15 min， and then by pump injection at 0.5 μg/（kg·h） till the end of operation； control group was given constant volume of 0.9％ Sodium chloride injection， ivgtt. cTnⅠ，IMA，SOD and MDA levels and the occurrence of ADR were observed in 2 groups after entering the operation room （T1）， at the end of vascular anastomosis （T2）， 6 （T3）， 12 （T4）， 24 h （T5） after operation. RESULTS： IMA of observation group at T2， T3 and T4 were significantly lower than those of control group， and cTnI at T2， T3， T4 and T5 were significantly lower than those of control group， with statistical significance （P＜0.05）. There was no statistical significance in SOD level at T1， T2， T3， T4 and T5 between 2 groups （P＞0.05）. Serum level of MDA in 2 groups at T4 and T5 were decreased significantly， and the observation group was lower than the control group， with statistical significance （P＜0.05）. No obvious ADR was found in 2 groups. CONCLUSIONS： Dexmedetomidine can protect cardiac muscle of elderly patients with OPCABG to certain extent， and relieve myocardial injury with good safety.