Fine grain wheels are used to fulfill high precision grinding. However, fine grain wheels have a common weakness, that is, the grains are easily torn loose from the wheel surfaces even under normal grinding conditions because of their small bonding areas, resulting in bad machining precision and low efficiency. Since ten years, SiC whiskers (fine fibers) have been extensively used as reinforcing material for metal, ceramics, plastics and composites because of their excellent mechanical, physical and chemical properties such as high hardness, high strength, high wear-resistance and good compatibility [1～2] . The average diameter of SiC whiskers is about 50μm and their length in the range of several micrometers, thus has a relatively larger bonding areas than fine grain of the same diameter. As a result, whisker grinding wheels composed of SiC whiskers as abrasives and phenol resin bond have been developed by Japanese professors K. Yamaguchi and I. Horaguchi and Chinese professor Y. Q. Wei since 1993 [3～5] . In this new wheel, the whiskers are directionally aligned and uniformly set normal to the grinding wheel surface, and their ends are served as cutting edges or tips. To examine the grinding performances of the freshly SiC whisker wheel, a large number of grinding experiments of difficult-to-cut materials such as hardened die-steel SKD11 (HRC60) have been carried out in this paper. The investigations have shown that the whisker wheel has very high grinding ratio (over 6000) and high efficiency, and that a nanometer level ground surface with roughness values of Ra 1.5nm and Ry16nm can be achieved.