Objective To investigate the effects of Levosimendan on acute kidney injury in patients undergoing coronary artery bypass grafting. Methods Patients with severe coronary artery bypass grafting were prospectively enrolled during December 2013 to June 2015 in Fuwai Hospital,randomized to levosimendan-treated group and control group.Results : 79patients were enrolled in the research,44patients in levosimendan-treated group and 35patients in control group.The creatinine were both increased in the two groups compared to baseline.The levosimendan group had lower creatinine than control group from Day 3,p<0.05 .The incidence of AKI in levosimendan group was less than control group.Multivariate logistic regression showed that levosimendan was the protective factor of postoperative AKI, OR :0.68(0.42~0.87). Conclusion Levosimendan reduced the incidence of AKI in the patients undergoing severe coronary artery bypass grafting.