The main feature of rotary ball valve is that it can not only shut off reliably in forward pressure, but also in reverse pressure or reverse pressure far greater than forward pressure. On the two sealing surfaces of the sealing pair, advanced technologies such as space plasma spraying, ether laser sputtering and vacuum protection infiltration surfacing can be used to form gradient functional materials such as martensitic stainless steel, austenitic stainless steel, cemented carbide, cermet and synthetic diamond. It can automatically align the center and compensate the wear automatically. When the ball valve is closed, the energy of the medium in the ball valve is fully utilized, and the high sealing specific pressure is automatically applied to make the high hard sealing pair achieve reliable zero leakage. There is no friction between the sealing pairs for instant closing and opening. The main structure of rotary ball valve is similar to butterfly valve, which has the characteristics of short structure and small volume of butterfly valve, so it can be used to manufacture valves with extra large diameter and large diameter.