The utility model relates to a be applied to continuous casting and open prefab of process of watering sets up the overhead side of dummy ingot, including first plate and second plate, first plate and second plate intersection and separate into four regions, the through -hole has been offered on first plate and the second plate. First plate and second plate cross. First plate or second plate have ascending extension, the through -hole has been seted up on the extension. The continuous casting is opened and to be watered when sealing the dummy ingot, places the prefab at the overhead face of dummy ingot, becomes four small regions with the crystallizer region -dependent segmentation of the overhead face of dummy ingot, and four small regions are convenient for open the intersection of watering cold strip and are put. Help saving the time of sealing the dummy ingot, improve work efficiency, reduce to open and water the materials used, reduce to open and water the accident rate.