The invention relates to a high-level liquid control device. The high-level liquid control device is characterized in that a valve body is made of plastic, the lower end of the valve body is provided with a water inlet with an inner thread, a hexagon screw head is arranged at the outer end of the valve body, a flat circular hole the same with the valve body in width is formed in the side face of the lower end of the valve body, the upper end and the lower end are semicircles, and edges are arranged on the periphery; a circle of groove is formed in the edge face, screw holes corresponding to a blind plate are symmetrically distributed in the inner side of the groove; the upper side of the interior of the valve body is provided with a 60-degree regular cone sealing port; the center line of the regular cone sealing port and the center line of the valve body are located on the same straight line; a flat protrusion with a hole is formed right in the middle of the upper end in the flat circular hole, the outer edge of the flat circular hole is provided with a circular boss, a columnar countersunk head through hole with an inner thread is formed in the middle of the flat circular hole, and a blind hole is formed in the inner wall of the opposite side. The high-level liquid control device has the beneficial effects that the application range is wide, the water control effect is good, a large amount of manpower and a large number of material resources can be saved, the service life is long, damage is not likely to happen, and maintaining is simple.