Objective To investigate the impact of edaravone on serum reactive oxygen species during the perioperative period of off-pump coronary artery bypass grafting （OPCAB）. Methods A total of 40 patients who underwent selective OPCAB in the First Hospital of Hebei Medical University between June 2011 and November 2012 were prospectively enrolled in this study. All the patients were randomly divided into a trial group and a control group by a random digitaltable method with 20 patients in each group. There were 13 males and 7 females in the trial group with their age of 40-67（51.8±11.5） years， and 9 males and 11 females in the control group with their age of 42-70 （53.5±13.1） years. Afteranesthesia induction， patients in the trial group received continuous intravenous infusion of edaravone 60 mg （diluted in 100 ml saline）， while patients in the control group received continuous intravenous infusion of saline 100 ml， both of whichwere finished within 30 minutes. Venous blood samples were taken 24 hours preoperatively （T1）， 1 hour after skin incision（T2）， at the end of the surgery （T3） and 24 hours postoperatively （T4） to examine the concentration of superoxide dismutase（SOD） and malondialdehyde （MDA）. The data of the two groups were compared. Results All the patients successfully underwent their surgery and were included in the analysis. At the T2， T3 and T4 time point， SOD concentration was 80.3±21.3 U/ml， 78.5±17.4 U/ml and 81.4±17.5 U/ml， and MDA concentration was 10.2±1.8 nmol/ml， 11.3±1.9 nmol/ml，14.8±2.1 nmol/ml respectively in the control group；SOD concentration was 92.8±18.4 U/ml，90.0±18.1 U/ml，and 88.7±18.7 U/ml，and MDA concentration was 7.2±1.7 nmol/ml，8.2±1.2 nmol/ml，10.2±1.3 nmol/ml respectively in the trial group. At each above time point， SOD activity was significantly higher in the trial group than the control group （F=2.90，P=0.003；F=2.80，P=0.003；F=2.80，P=0.001）， and MDA concentration was significantly lower in the trial group than the control group （F=2.79，P=0.001；F=2.80，P=0.001；F=2.90，P=0.000）. Conclusion Edaravone can decrease serum reactive oxygen species caused by OPCAB and reduce myocardial injury.