Abstract: OBJECTIVE To discuss the clinical significance of combination procalcitonin (PCT) with D- dimer (D-D) in the detection of acute infection in patients from emergency department. METHODS A total of 516 cases of acute infection in emergency department in our hospital from Jan. 2014 to Dec. 2015 were selected as research objects. Acute physiology and chronic health evaluation (APACHEⅡ) score in patients admitted to hospital within 24h were evaluated. The PCT and D-D levels in patients were detected, and the clinical significance for condition evaluation was analyzed. RESULTS D-dimer, acute physiology score and APACHEⅡof group D and group C were higher than those of group A and group B, and the difference was statistically significant(P＜0.01). PCT, acute physiology score and of APACHEⅡscore of group G with different D-D levels were higher than those of group E and group F, and the difference was statistically significant(P＜0.01).Acute physiology score and of APACHEⅡscore of group H were higher than those of group I and group J, and the difference was statistically significant(P＜0.01).PCT, D-D levels and APACHEⅡ scores were significantly positively correlated with each other (P＜0.01). CONCLUSION Detection of PCT combined with D-dimer can better judge the condition of patients with acute infection, which has more advantage compared with using PCT or D-dimer alone.