Abstract: The micro-hole processing test of nickel-based single crystal superalloy was carried out to investigate the effects of electrodes with different diameters and different cross-section shapes on the dimensional accuracy， surface quality， processing efficiency and subsurface damage of micro-holes. The results showed that the processing efficiency of micro-holes processed by the micro-spiral electrode is much larger than that machined by the cylindrical electrode. The processing efficiency of micro-holes machined by the micro-spiral electrode with the 200μm diameter is 17% higher than that by the cylinder electrode of the same diameter processed， and the processing efficiency of micro-holes processed by the micro-spiral electrode with the 300μm diameter can be increased by 30.56%. The micro-hole reaming machined by the micro-spiral electrode is smaller than that made by the cylindrical electrode， and the quality of the pore wall obtained by the micro-spiral electrode is better than that machined by the cylindrical electrode. The subsurface damage layer of the micro-hole processed by the micro-spiral electrode is continuous and the thickness is smaller than that of the micro-hole processed by the cylindrical electrode.

Key words: micro-spiral electrode, micro-cylinder electrode, micro-hole, CuW70, nickel-based single crystal superalloy