Tilting Disc Swing Check Valve design with a butterfly stype disc installed on the valve stem. The valve seat is floating elastic metal seal type. It could help the seat adjust contacting with the valve disc automatically. The valve seat sealing surface is a part of the inclined cone, the sealing line formed between the valve seat and the valve disc is approximately elliptical curve. The angle between the plane of the curve and the valve flow centerline is 60 degrees, the long axis center of the approximate ellipse sealing line and the cone axis form an angle eccentricity, that is, the axis of the cone of the valve seat sealing surface and the center line of the valve body flow path form a second eccentric angle of 15 degrees to 20 degrees, the valve disc rotation axis and the axis of the cone forms an eccentric amount, it is also in an eccentric position with respect to the plane of the seal line, forming an eccentric amount.