CD4+CD25+Foxp3+ regulatory T cells(Treg) are new focuses during perioperative immune function changes. Although several issues need to be addressed, Treg-based monitor method is a promising evaluation modality that is applicable to a wide use of perioperative immune appraising. To evaluate the perioperative changes of immune function and to provide an important basis for the rational use of anesthesia-related drugs. The article discusses recent findings regarding Treg, including the physiological roles they play, how these cells are involved in the pathophysiology of common diseases and how anesthesia-related drugs affect them.