For the plug valve which can have multi-passageway structure but no internal cavity, the plug rotates around the vertical axis of the valve body by 90°to open or close the passageway. Generally, the plug valves can be widely applied as the equipment for cutting off and distributing the medium and changing the medium flow direction in the fields of oilfield exploitation, transporting and refining equipment, petrochemical product, coal gas, heating and ventilation industry, and the plug valves configured with pneumatic or electric actuators, etc. can be used to realize remote operation. More