Sepsis is a common cause for morbidity and mortality in critically ill patients. With the development of medical skills, the mortality is still remain very high. Inappropriateness of initial antibiotic treatment is an important risk factor for mortality and effective antimicrobial administration within the first hour of documented hypotension was associated with increased survival to hospital discharge in adult patients with septic shock. However, the early treatment based on early diagnosis.But it is very difficult to diagnosis because of lack of specific clinic symptom and sign.When severe sepsis occur, biomarker could be helpful to diagnosis. Unfortunately, the diagnostic value of single biomarker is limited. Therefore, combine several biomarkers could enhance the diagnostic value.