Objective To explore the relationship between perioperative hemoglobin (HGB) concentration and acute kidney injury (AKI) after pulmonary lobectomy. Methods Patients, who received selective pulmonary lobectomy under general anesthesia in Peking University First Hospital from July 2017 to December 2019, were recruited and divided into low HGB group (HGB<120.0 g/L; n=230) and normal group (HGB≥120.0 g/L, n=1522) according to the HGB concentration before surgery. And the primary endpoint was the incidence of AKI after surgery. Multivariate logistic regression model was used to analyze the influence of preoperative HGB, minimum HGB concentration during surgery and the decrease of HGB concentration after surgery on postoperative AKI. Results A total of 1752 patients were involved in the study, and the overall incidence of postoperative AKI was 2.3%. The incidence of AKI was significantly higher in low HGB group than in normal group [5.7% (13/230) vs. 1.8% (28/1522), RR=3.197, 95%CI 1.631-6.266, P=0.001]. Multivariate logistic regression analysis showed that the risk of postoperative AKI increased to 3.590 (95%CI 1.765-7.303, P<0.001) times if preoperative HGB concentration being lower than 120.0 g/L, and that the risk of postoperative AKI increased to 2.751 (95%CI 1.633-4.635, P<0.001) times for every 15.0 g/L reduction of preoperative HGB. Moreover, the independent risk factors involved preoperative eGFR <60 ml/ (min.1.73 m²), intraoperative infusion rate <5 ml/ (kg·h) and intraoperative urine output <0.8 ml/ (kg·h) (P<0.05). In addition, multivariate logistic regression models also showed that minimum HGB concentration during surgery (OR=0.933, 95%CI 0.780-1.114, P=0.442) and the decrease of HGB concentration after surgery (OR=0.900, 95%CI 0.630-1.287, P=0.565) were not independent risk factors of postoperative AKI. Conclusion Preoperative HGB <120.0 g/L is an independent risk factor of postoperative AKI after pulmonary lobectomy.