[Background] Vascular permeability is defined by the combination of transcellular and paracellular pathways, with the latter being a major contributor to the increasing of vascular permeability in the process of inflammation. Tight junction is the important component of paracellular pathways. The destruction of tight junction will induce the increasing of vascular permeability. [Objective] Objectives of this article are to analyze signaling mechanisms of tight junction and understand its function of protecting blood vessels barriers. [Content] This article reviews several important signaling mechanisms which affect the tight junction，explains how it effect cell permeability through delivering and regulating information. [Trend] The integrity of tight junction can restrain the generation of edema fluid and future research will focus on its specific application in inflammatory disease, in order to diagnose better and predict development and therapeutic effect of disease.