Cooling device enhancing online cooling effect on high-speed bar

A cooling device enhancing the online cooling effect on a high-speed bar comprises a cooler which comprises a water-cooling outlet end. The cooling device further comprises a water return device which comprises a water tank. The top of the water tank is connected with a water drain pipe, a first outlet guide pipe and a second outlet guide pipe are installed on side walls of the water tank, the first outlet guide pipe is in butt joint with the water-cooling outlet end of the cooler, the second outlet guide pipe and the first outlet guide pipe are arranged in a spaced mode, and the centerline of the cooler, the centerline of the first outlet guide pipe and the centerline of the second outlet guide pipe are located on the same straight line. According to the cooling device, the water return device is additionally arranged at the tail end of the cooler, so that only a part of cooling water entering the cooler is discharged from the second outlet guide pipe on one side wall of the water tank, most cooling water is accumulated in the cooler and the water tank, definite pressure is formed in the cooler, eddies are formed under the action of cooling elements, cooling water forming the eddies can quickly scour water vapor attached to the surface of steel, and accordingly steel surface temperature is rapidly decreased.