K9 glass is extensively used as high end optical element material. However, K9 glass is a difficulttocut and hard material. In order to achieve high grinding efficiency, reduce subsurface damage and difficulty of postproduction as well as procedure cost, many researchers research K9 machining technology. Brazed grinding wheel has the advantages of high grit protrusion and easily orderly setting of gits. Consequently, brazed diamond grinding wheel was used to precisely grind K9 glass. The change of grinding wheel during dressing was studied and the ground surface changes of K9 glass as process parameter variation were observed.The experimental results indicate that flat wear and edge passivation and some other grit forms occur. Ground K9 glass surface is made up of grinding mark glazing area and some spalled pits. 