A universal combination prestress clamp suitable for various machine tools comprises prestress application components and prestress maintaining components, the prestress application components include a mechanical prestress application component and a hydraulic prestress application component, the prestress maintaining components include a plane milling-grinding workpiece prestress maintaining component and an external turning-grinding workpiece prestress maintaining component; the plane milling-grinding workpiece prestress maintaining component and the external turning-grinding workpiece prestress maintaining component are used with the mechanical prestress application component or the hydraulic prestress application component. In actual use of the prestress clamp, part of the parts in the clamp are common parts, only one set of these parts needs to be prepared, and other parts in the clamp are replaced suitably according to the prestress machining requirements of different workpieces to finally assemble an actually required prestress clamp. The prestress application device is updated to a universal phase for the first time, is suitable for use on various types of machine tools, and is suitable for workpieces of different sizes or shapes.