Background Interleukin（IL）-15， which is one of important T lymphocytes growth factors， is one member of the cytokines family with 4-αhelix in their molecules. Recently， theory of trans-presentation（TTP） of IL-15 and its roles in inflammatory responses have been widely studied.　Objective　To review the theory of trans-presentation of IL-15 and its mechanism of IL-15 in inflammatory responses.　Content　IL-15 plays signifficant roles in cytokines responses， lymphocytes， neutrophils and monocytes / macrophages. The cytokine can fight against various pathogens and neoplasms， and can function as an antiapoptotic molecule. It was reported that trans-presentation model， the dominating mechanism inducing IL-15 responses， is one direct and controllable pattern in which way IL-15 is presented to effector cells. At first， IL-15 in cells combines to IL-15R； then the IL-15-IL-15R complex transpresents through membrane to external surface， and fixs on it. Finally， IL-15 functions in the way of paracrine. Dendritic cells may be the main transpresenting cells in this process. IL-15 promotes inflammatory responses by multiple mechanisms， one of which is IL-15- dendritic cells-GSH mode.　Trend　The type and phage of inflammatory responses， and the role of IL-15 need further research.