The sand control flat valve is widely used in the fracturing wellhead of oil and gas well equipment and the high-pressure manifold with large sand content, when the medium with large sand content flows through the valve body, the gravel easily enters the valve cavity, increases the maintenance frequency of the valve, and shortens the service life of the valve. The double-seat sand-proof Flat Valve consists of inner and outer seats, the inner seat is inlaid and the inner part of the outer seat is provided with a sand-proof ring. It has high value of industrial application