As a component used to achieve pipeline system access and flow control, the midline butterfly valve has been extremely widely used in many fields such as petroleum, chemical, metallurgy, hydropower and so on. In the known butterfly valve technology, its sealing form mostly uses sealing structure, sealing material is rubber, PTFE, etc.. Due to the limitations of the structural characteristics, it is not suitable for high temperature resistance, high pressure and corrosion resistance, anti-wear and other industries.