Abstract: Bearings are precision machine Components. Surface machining technologies especially the grinding process, have significant influences on the surface quality and their working life. In the present investigation, a series of experimental techniques, such as light and electron metallo graphy, micro-hardness measurement, x-ray diffraction, electron microprobe, Auger electron spectroscopy, radioisotope wear testing, etc, were used to study the grinding affected surface ayer of GCrl5 steel plate specimens and miniature bearing races employing different grinding Parameters. The results showed that the superficial surface layer, comprising a microstructure of tempered martensite with uniformly dispersed fine carbide precipitates in the matrix, had higher hardness and better wear resistance than otherwise. By adopting an improved grinding process inferred from the present investigation, the wear resistance of miniature bearings could be appreciably enhanced.