Abstract: Sepsis is thought to be systemic inflammatory response syndrome that is activated by invasive infection and characterized by the involvement of inflammation,infection,immunological reaction,coagulation and tissue damage.The imbalance between the pro-and anti-inflammatory response mediated by immunologic disorder plays an important part in the progress of sepsis.Therefore,the immunological mechanisms and changes of Toll-like receptors,neutrophils,dendritic cells and regulatory T cells in sepsis are briefly focused on in the article.