The valve is small in size and light in weight. It can be used as a device to cut off and regulate flow in various medium pipelines. By selecting valve plates and seals of different materials and connecting plates and shafts without pins, it can be used in worse working conditions, such as desulfurization, vacuum and desalination systems. The butterfly valve with convex ears can repair the downstream pipeline and equipment of the valve on-line, and the valve can be realized. The downstream pipeline and equipment of the valve are repaired online, and the valve can be installed at the end of the pipe as an exhaust valve. The valve is used in petroleum, chemical, food, medicine, paper making, hydropower, ship, water supply and drainage, smelting, energy and other systems. It can be used as a regulating and closing device for a variety of corrosive, non-corrosive gases, liquids, semi-fluids and solid powder pipes and containers. Ready to use.