Fas/FasL mediates an important signal pathway cell apoptosis. Recent studies showed that it can stimulate the secretion of proinflammatory cytokines and induce inflammatory reaction. Inaddition, it also participates in a variety of biological activities such as immune privilege, immune escape and tumor formation and metastasis. FasL may also act as a receptor to deliver reverse signals, stimulating cell proliferation and paticipating in the development of some autoimmune diseases.