During the operation of chemical plant, high temperature, high pressure, toxic and flammable medium leakage lead to safety and environmental threats, so the leakage should be solved by the pressure sealing technology. The principle of the pressure sealing and plugging technologies, and its application and effect in the chemical plant were introduced. The common sealing technologies were explained in detail. It is pointed out that the pressure and plugging has become a essential technology for chemical enterprise to reduce losses and make "no leak factory", become a kind of routine maintenance mode for chemical plant.