Abstract: Sepsis induced by burns, trauma, and surgical stress, remains a major cause of death of patients in ICUs. A growing number of evidence shows that sepsis may result in dysfunction of innate and adaptive immune system, including the abnormal disorder of immune response of T lymphocytes, regulatory T lymphocytes, and dendritic cells, resulting in a state of immune depression. It is of great significance that dynamic monitoring of immune function and the related indicators might help to assess the risk of secondary infection, the prognosis of septic patients, and to guide the treatment of severe sepsis.