OBJECTIVE To investigate the eff ects of hypoalbuminemia and human albumin supplementation on patients with acute kidney injury （AKI）after off-pump coronary artery bypass grafting （OPCABG）. METHODS From December 2018 to January 2020，clinical information of 484 patients with coronary atherosclerotic heart disease who underwent selective OPCABG in Tianjin Chest Hospital were analyzed retrospectively. The basic data ，American Society of Anesthesiologists （ASA）grading，the number of coronary artery bypass grafting ，amount of intraoperative bleeding ，use of artificial colloid ，minimum value of hemoglobin within 7 days after operation ，hypoalbuminemia occurred after operation ，monitoring time in postoperative intensive care unit ，drainage volume of thoracic catheterization ，perioperative blood transfusion ，amount of human albumin after operation were summarized. All patients were divided into non-AKI group （414 cases）and AKI group （70 cases）according to the occurrence of AKI. The differences of the above indexes between the two groups were compared. Multiple Logistic regression analysis was performed to analyze the risk factor of AKI when selecting the indexes with P＜0.1. According to whether hypoalbuminemia occurred after operation ，all patients were divided into normal protein group （347 cases）and hypoalbuminemia group （137 cases）. Hierarchical analysis was carried out to explore the correlation between human albumin supplementation and AKI. RESULTS The results of multiple Logistic regression analysis showed that there was no significant effect on AKI in postoperative hypoalbuminemia （P＞0.05），but there were significant effect in body mass index and the dosage of postoperative human serum albumin （P＜0.05）. The risk of AKI would increase by 12.7％ every time the body mass index increases by 1 unit；the risk of AKI increased by 17.3％ for every 10 g increase in the dosage of human albumin. Stratified analysis showed that the risk of AKI would increased by 26.9％ for every 10 g increase in postoperative human albumin supplementation in normal protein group and 14.0％ for every 10 g increase in postoperative human albumin supplementation in hypoalbuminemia group. CONCLUSIONS Hypoalbuminemia is not a risk factor fo r the development of AKI after OPCABG ，but human albumin supplementation is a risk factor for AKI after OPCABG.