Cellular FADD-like interleukin-1-β converting enzyme inhibitory protein (c-FLIP) is a kind of inhibitory protein of caspase with the death effector domain (DED), naturally existing in many species such as virus, eukaryote and mammal inclusively. Recently, it has been discovered that c-FLIP participates the regulation of apoptosis. Overexpression of c-FLIP may inhibits the apoptosis induced by the death receptor of Fas and TRAIL-R. With the development on the mechanism of action and molecular regulation of c-FLIP, its multi-biology function has been found, and also it is associated with the nosogenesis and progression of many diseases.