A valve that is rotated around a valve shaft to open and close, primarily to cut and throttle the pipe. The butterfly valve opening and closing member is a disc-shaped butterfly plate that rotates around its own axis in the valve body for opening and closing or adjusting purposes. Butterfly valve full open to full close is usually less than 90°, butterfly valve and butterfly rod itself has no self-locking ability, in order to butterfly plate positioning, to install a worm gear reducer on the valve stem. The worm gear reducer can not only make the butterfly plate have self-locking ability, make the butterfly plate stop in any position, but also improve the operating performance of the valve. The characteristics of industrial butterfly valve can withstand high temperature, applicable pressure range is also higher, the valve nominal size is large, the body is made of carbon steel, valve plate seal ring using metal ring instead of rubber ring. The large-scale high temperature butterfly valve is made of welded steel plate, which is mainly used for smoke duct and gas pipe of high temperature medium.