Abstract: AIM To evaluate the effects of off-pump coronary artery bypass graft (CABG) surgery in treatment of coronary atherosclerotic heart disease. METHODS One hundred and seventy patients with coronary atherosclerotic heart disease were randomly divided into on-pump CABG group (on-pump group, n=85 cases) and off-pump CABG group (off-pump group, n=85 cases). The transfused blood volume, postoperative chest drain loss, oxygenation index (OI), alveolar-arterial oxygen gradient (AaDO2), inotropic support, myocardial enzyme, extubation time and length of stay in ICU were observed. RESULTS In the off-pump group, postoperative bleeding and transfusion were reduced significantly, AsDO2 and OI were better and the length of inotropic drug support, myocardial enzyme changes and complications were less than those in the on-pump group. Extubation time and length of stay in ICU were shorter in off-pump group. CONCLUSION Off-pump CABG attenuates myocardial and lung injuries, reduces blood transfusion, lowers complication rates and relieves patient pain. Thus, it is worth clinical promotion.