Sepsis is whole body inflammation in response to microbial infection,which leads to life-threatening organ dysfunction.It can also lead to sepsis shock (sepsis with circulatory disorder and cell metabolic disorder),the death risk of which increased obviously,and has become one of the world’s ten causes of human death.It is becoming a frequent complication of the patients in the intensive care unit.Therefore,the early and differential diagnosis and rational antibiotic treatment are the key factors to determine the prognosis of sepsis.Procalcitonin (PCT),a precursor of calcitonin,is very low in the blood of healthy people.In the case of systemic bacterial infection,the level of PCT in the blood increases rapidly,and the degree of its elevation is associated with the severity of the disease.This feature enables PCT to be one of the serum bio-markers for sepsis or septic shock and is more sensitive and specific than traditional bio-markers (C reactive protein).The dynamic monitoring of PCT can reflect the body sensitivity to the antibiotic treatment and guide the course of it.This article summarizes the clinical value of PCT in early diagnosis of sepsis and guiding the antibiotic treatment of sepsis.PCT may be a good indicator for early diagnosis of sepsis.It can also assess the severity of sepsis,guide the treatment of antibiotics,reduce antibiotic resistance and shorten the course of treatment.The single PCT index still has some limitations in the accuracy and application scope.The combination of PCT and other biomarkers as a more reliable diagnostic and therapeutic index is the development prospect in the future.