The development of the ability to machine glass materials to optical tolerances is highly desirable. The machinability of glass is poor in diamond cutting due to the high hardness and the high brittleness of glass. In order to investigate the effects of cutting fluids on the machinability of glass, this paper selected boric acid solution and sodium carbonate solution as cutting fluids, and then scratching tests were carried out. The resulting scratches with and without cutting fluids was assessed based on the observations of the micro-morphology of the scratched grooves utilizing confocal microscope. Experimental results indicated that compared with the process without cutting fluids action, the machinability of glass BK7 can be improved by using boric acid solution or sodium carbonate solution as the cutting fluids.