Objective To systematically evaluate impact of perioperative use of clopidogrel on coronary bypass grafting (CABG) patients for anti-platelet treatment, in order to provide evidence for the rational drug use of such patients in the perioperative period. Methods PubMed, EMbase, HighWire, CENTRAL and its affiliated clinical trial registered data center, CBM and CNKI were electronically searched from 2003 to November, 2012. Randomized controlled trials (RCTs) and non-randomized clinical trials on perioperative use of clopidogrel of CABG patients were collected. References of included studies were also retrieved. Two reviewers independently screened studies according to exclusion and inclusion criteria, extracted data, and assessed the methodological quality. Then, meta-analysis was performed using RevMan 5.0 software. Results 18 studies (including 10 RCTs and 8 non-randomized clinical trials) involving 14 592 patients were included. The results of meta-analysis showed that: a) Among 10 included RCTs, preoperative use of clopidogrel for anti-platelet treatment reduced the incidence of myocardial infarction obviously, compared with the blank control group (RR=0.63, 95%CI 0.48 to 0.83, P=0.000 9), but there is no significant difference between the two groups in blood loss amount within 24 hours after operation (MD=130, 95%CI –6.21 to 266.22, P=0.06), the number of reoperation patients because of bleeding (RR=1.42, 95%CI 0.92 to 2.20, P=0.12), and risk of postoperative short-term death (RR=1.19, 95%CI 0.89 to 1.58, P=0.24); b) Among 8 non-randomized clinical trials, there was no significant difference between the two groups in reducing the incidence of myocardial infarction (RR=0.83, 95%CI 0.30 to 2.26, P=0.71), but preoperative use of clopidogrel for anti-platelet treatment significantly increased blood loss amount within 24 hours after operation (MD=82.42, 95%CI 35.18 to 129.66, P=0.000 6), the number of reoperation patients because of bleeding (RR=1.71, 95%CI 1.07 to 2.75, P=0.03), and risk of postoperative short-term death (RR=1.89, 95%CI 1.15 to 3.12, P=0.01). Conclusion Current evidence shows that, perioperative use of clopidogrel can reduce the incidence of myocardial infarction, but doctors should consider cautiously the increased risk of bleeding, re-operation and postoperative short-term death. There is contradiction between the results of RCTs and those of non-randomized clinical trials, which may result from the argument intensity, quantity and sample size bias of the included studies. The above conclusion should be proved by large-scale high-quality RCT results in future.