Disclosed is a process for preparing metal oxide slurries suitable for the chemical mechanical polishing (CMP) of semiconductor devices. A suspension of metal oxide in water is dispersed at a predetermined pressure through an orifice of a dispersion chamber while two intensifier pumps are used to maintain the pressure applied to the dispersion chamber constantly, resulting in restraining or minimizing the generation of macro particles as large as or larger than 1 &mgr;m. The metal oxide slurries are uniform in particle size with narrow particle size distribution and show excellent polishing performance with a significant reduction in the occurrence frequency of microscratches, so that they are suitable for CMP of ultra-integrated semiconductor devices.