Tensioning device for cylinder block workpiece

The invention relates to a tensioning device for a cylinder block workpiece. The tensioning device comprises a mounting base, a tensioning rod and a connecting part, wherein the mounting base is arranged on a machine table in a sliding manner; a sliding groove is formed in the mounting base; the first end of the tensioning rod is arranged in the sliding groove in a sliding manner; the sliding direction of the mounting base intersects with the sliding direction of the tensioning rod; the second end of the tensioning rod is movably connected with the first end of the connecting part; the second end of the connecting part is detachably connected with the bottom of the cylinder block workpiece, and under the condition that the tensioning rod is rotated, the connecting part drives the cylinder block workpiece to move in the direction close to or away from the machine table. According to the tensioning device, the problem that the cylinder block workpiece is difficult to position in the machining process at present