Objective To study the prognostic value of arterial blood lactate clearance rate in patients with sepsis. Methods The clinical data of sepsis patients who were treated from January 2011 to December 2012 in our intensive care unit were retrospectively analyzed. They were divided into the survival group and the dead group according to different outcomes. The lactate clearance rates at 6 h after admission were compared between the two groups. The area under the ROC curve (AUC) was calculated and the best cut-off value of arterial blood lactate clearance was used to evaluate the prognosis of sepsis. Then the patients were divided into the high lactate clearance group and low lactate clearance group, and the values of lactate, procalcitonin (PCT), acute physiology and chronic health evaluation Ⅱ (APACHE Ⅱ) score, sepsis-related organ failure assessment (SOFA) score and mortality were compared between the high and low lactate clearance groups. Results A total of 84 patients were finally included in this study, with 48 in the survival group and 36 in the dead group. The levels of arterial blood lactate on admission ([2.31±1.39] mmol/L and [3.93±1.84] mmol/L, P<0.01) and arterial blood lactate clearance rates at 6h after admission ([44.01±27.37]% and [10.49±24.53]%, P<0.01) were significantly different between the two groups. The AUC of lactate clearance rate, APACHEⅡ score and SOFA score were 87.15%, 77.89% and 84.84% for predicting sepsis, respectively. The Youden Index reached the peak value (0.72) when the lactate clearance rate was 31%. The APACHEⅡ score, SOFA score and mortality rates were significantly different between the high lactate clearance rate group (≥ 31%) and the low lactate clearance rate group (<31%, P<0.05). Lactate clearance rate was an independent risk factor of prognosis in sepsis patient (OR=0.021,95%CI 0.002-0.237, P=0.002). Conclusion Arterial blood lactate clearance may serve as a promising index for predicting prognosis of sepsis.