Purpose: Acute kidney injury (AKI) could increase the risk of mortality after cardiac surgery. We aimed to explore the predictive value of hyperlactatemia in AKI in patients undergoing type A aortic dissection (TA-AAD) operation. Methods: A total of 337 consecutive patients who underwent TA-AAD surgery in Beijing Anzhen Hospital from February 2009 to December 2013 were included into this study. Based on blood lactate level at 6 hours after surgery (median, 4.1 mmol/L), patients were divided into two groups: high (>= 4.1 mmol/L) and low lactic (< 4.1 mmol/L) groups. We examined the association between risk factors and AKI, especially the impact of postoperative lactate level on the incidence of AKI. Results: Of 337 patients, 152 (45.1%) patients had early postoperative AKI. 29 (8.6%) patients needed Continuous Renal Replacement Therapy (CRRT). There were 164 patients in the high lactate group and 173 patients in the low lactate group. Additionally, the rates of the AKI Stage 2-3 were also markedly different between the two groups (P<0.05). Furthermore, postoperative lactate level at 6 h was an effective predicator for AKI (OR, 1.284; 95% CI: 1.129-1.460; P<0.001; AUC, 0.767) and RRT (OR, 1.295; 95% CI: 0.737-0.891; P<0.001; AUC, 0.814). Lactate level of 5.05 mmol/L was the boundary value for AKI Stage 2-3 (sensitivity 71.0%, specificity 69.3%). Meanwhile, lactate level of 7.0 mmol/L was the boundary value for CRRT (sensitivity 73.9%, specificity 79.5%). Conclusions: Our study found that early postoperative lactate level was an effective predictor of AKI and CRRT for patients with acute type A aortic dissection.