Objective To compare the anticoagulant efficacy and safety of bivalirudin and heparin during percutaneous coronary intervention (PCI). Methods A total of 100 consecutive patients hospitalized in our center due to unstable angina from December 1st to 31st, 2018, and undergoing elective PCI were enrolled in this study. They were randomly divided into bivalirudin group (n=50) and heparin group (n=50). Their activated coagulation time (ACT) was monitored at 15,30, 60min after administration and at the end of the operation, and the occurrence of perioperative bleeding events and major adverse cardiovascular events (MACE) were observed. SPSS statistics 20.0 was used for data analysis.Results After 15min of administration, the ACT were up to the standard time in both groups. The ACT levels remained stable in the bivalirudin group [15min:(280.5±12.5)s; 30min:(279.5±5.5)s; 60min:(282.1±6.8)s; end of operation:(275.3±9.9)s], while those of heparin group continued to decline [15min:(276.6±6.1)s; 30min:(258.1±3.0)s; 60min:(241.8±8.6)s; end of operation:(234.9±7.9)s]. Significant difference was seen in ACT between the 2 groups from 30 min after administration (P＜0.001). There were no obvious differences in the prevalence of hemorrhagic events and thrombotic events between the 2 groups (P＞0.05). Conclusion Both bivalirudin and heparin are efficient and safe anticoagulants during PCI, and the former can obtain more stable ACT. While, for the latter, ACT should be monitored every 15 min due to its obvious fluctuation during the whole operation.