Disclosed is a floating diaphragm type electromagnetic valve. The floating diaphragm type electromagnetic valve mainly comprises a valve body, a valve cap, a diaphragm component and a pilot-operated head, the valve cap is located on the valve body and fixed by a hexagon socket cap screw, the diaphragm component is placed between the valve cap and the valve body, the upper end of the valve cap is connected with the pilot-operated head in a spiral mode, a groove is mounted on the valve cap, a large O-shaped ring which is in contact with the end face of the valve body is placed in the groove, a groove is arranged on the valve body, a small O-shaped ring which is in contact with the end face of the valve cap is placed in the groove of the valve body, and the two O-shaped rings are staggered. The floating diaphragm type electromagnetic valve has the advantages that a diaphragm is arranged between the valve body and the valve cap along the edge, a gap of about 0.5mm between the diaphragm and the valve body is reserved, a gap of about 0.5mm between the diaphragm and the valve cap is reserved, so that the diaphragm can not be tightly pressed by the valve body and the valve cap, when a valve is opened or closed, floating stretching can be achieved, and advantages of high action reliability of a rubber diaphragm and good fluid medium resistance of a piston valve are combined.