Central point positioner of clamp and clamp

The utility model discloses a central point positioner of a clamp and the clamp. Supporting legs on a base penetrate through threaded holes to limit the mutual positions of the base and a lower clamping sheet when the base and the lower clamping sheet are connected together, that is the base and the lower clamping sheet are stacked spatially; at the moment, the projection position of a positioning hole in the center of the base is positioned at a central point of the lower clamping sheet, so that the problem that preparation of a sample fails because a chip is deflected from the central point, which is selected by eyes, of the lower clamping sheet in a process of preparing the sample for a destructive tension test is solved; the chip is accurately attached to the central point position of the lower clamping sheet, so that the success rate of sample preparation is improved, and the time for the sample preparation process is shortened.