Eccentric rotating valve features novel design. It has features of approximately cylindraceous body and valve plug spherical surface centre offsets from the stem rotating centre. When the stem is driving the disc, the valve plug spherical surface rotating offsets from the body centre by Cam-shape track curve. When valve is closing, the flexile stem of the valve plug occurs elastic deformation making the valve plug spherical surface gets closer to the seat for achieving reliable sealing. Equipped with pneumatic or electric actuator cooperating with accessories like positioner or solenoid valve, it can achieve adjusting by ratio. Soft seal and metal seal are optional sealing types.