Objective To investigate the effect of preoperative serum uric acid level on the incidence of acute kidney in-jury after off-pump coronary artery bypass grafting and to discuss whether serum uric acid level is an independent predictor of postoperative acute kidney injury.Methods A total of 631 patients undergoing off-pump coronary artery bypass grafting in Anzhen Hospital from January 2018 to June 2018 were reviewed.Patients were divided into high uric acid group(higher-than-median)and low uric acid group(lower-than-median) , based on the preoperative serum uric acid level of the patients.The de-mographic variables, comorbidities, the chelsea comorbidity index, preoperative medication, serum creatinine level and glo-merular filtration rate were compared between the two groups.Meanwhile, intraoperative operative time, infusion volume, post-operative acute kidney injury staging and the rate of frozen plasma usage , continuous renal replacement therapy and reoperation rate were observed.Results Among the 631 patients, 83(13.2％, 83/631)cases developed postoperative acute kidney inju-ry, 65(78.3％, 65/83) cases had a higher level of preoperative serum uric acid above the median(OR =3.143, 95％CI:1.850-8.798, P=0.001).After adjustment, multivariate analysis showed that elevated level of serum uric acid and BMI >30 kg/m2, the increase of preoperative serum creatinine level, the decrease of glomerular filtration rate( <60 ml/min) and higher CCI score were associated with postoperative acute kidney injury independently .Intraoperative fluid volume , diabetes and preoperative diuretic administration did not relate to the incidence of acute kidney injury after cardiac surgery .Conclusion Elevated serum uric acid level can be a strong predictor for the incidence of acute kidney injury after off-pump coronary artery bypass grafting.