Objective To investigate the expression of serum procalcitonin in patients with sepsis and its influence on prognosis.Methods From December 2014 to December 2016,119 cases of sepsis patients were enrolled in the hospital.According to the severity of the disease,49 cases in the early sepsis group,37 cases in the severe sepsis group and 33 cases in the septic shock group.According to the prognosis of 28 d after admis-sion,the patients were divided into the survival group(95 cases)and the death group(24 cases).Serum procal-citonin was measured by double antibody sandwich enzyme-linked immunosorbent assay.The changes of WBC count,C reactive protein and APACHE Ⅱ score,serum procalcitonin level,serum procalcitonin level and sur-vival group and death group were compared.Results Septic shock of white blood cell count,C reaction protein and APACHEⅡ were higher than those of early sepsis group and severe sepsis group(P<0.05);severe sep-sis group cell counts,C reactive protein and APACHE Ⅱ were higher than those of early sepsis group(P<0. 05).The septic shock group of serum procalcitonin levels higher than the early sepsis group,severe sepsis group(t=33.136,21.863,P<0.05);severe sepsis group serum procalcitonin levels higher than the early sep-sis group(t=16.876,P<0.05).The level of serum procalcitonin in the death group was higher than that in the survival group(P<0.05).Conclusion The level of serum procalcitonin in patients with sepsis is obvious-ly higher.With the severity of the disease,the serum procalcitonin level is higher,and can be used as an indica-tor of prognosis evaluation.