Elastic seat ring sealed eccentric plug valve is a new structure valve which fills the blank of traditional plunger valve and ball valve in the applications like large- diameter pipeline (above DN200] and muddy water and sludge occasions. Owing to its excellent sealing performance and corrosion-resisting performance, smaller opening/closing torque and water-flow loss and long service life, it is applied as the regulator or closure in the work occasions such as urban sewage, industrial sewage, sludge and clear water.