Abstract: Objective：To explore effects of myocardial protection of sufentanil on patients performed off-pump coronary artery bypass grafting（OPCABG）. Methods：sixty patients ,52～75 years, with OPCABG selective operation, the ASA Ⅱ or Ⅲ, were randomly divided into the sufentanil group (S) and fentanyl group (Group F),（n=30 each）. Sufentanil 1 μg/kg was used in group S ,Fentanyl 10 μg/kg in group F , during anesthesia induction. Fentanyl 0.8 μg/kg was used to keep anesthesia in group S, Fentanyl 8 μg/kg in group F,at skin incision, in sternotomy, in clamping aortic sidewall, the end of operation respectively.The radial artery blood samples were obtained at these time points: before induction of anesthesia(T0), the end of the suture blood vessels (T1), the end of operation (T2), 8,16,24 hours after operation(T3, T4,T5). 10 ml serum in both groups cases were separated, which were measured interleukin 6 (IL-6), interleukin 10 (IL-10), creatine kinase isoenzyme (CK-MB), cardiac troponin I(cTnI) concentration and activity of superoxide dismutase enzyme (SOD) by enzyme-linked immunosorbent assay. Results：The concentration of cTnI in group F is lower than in group S significantly at T4～5 (P <0.05), the concentration of IL-6 is lower at T1～4(P <0.05), the concentration of IL-10 is higher at T1～4(P <0.05),the activity of SOD is higher at T1～3(P <0.05). Conclusion：Sufentanil have the effect of myocardial protection in the OPCABG, whose mechanism is in connection with anti-inflammatory, scavenging free radicals, reducing oxidative stress.