The invention relates to the technical field of ultra-hard honing, in particular to a preparation method of a mixed ultra-hard honing oil stone. The preparation method of the mixed ultra-hard honing oil stone is characterized in that diamond with the surface being subjected to tungsten-plating metallization and cubic boron nitride (CBN) with the surface being subjected to tungsten-plating metallization are used for preparing the honing oil stone as abrasive materials. The preparation method comprises the steps that firstly, the molten salt process and magnetron sputtering tungsten-plating pretreatment are conducted on diamond abrasive particles and CBN abrasive particles; secondly, the pretreated abrasive particles and metal bonding agent powder are subjected to ball milling after being mixed according to a certain proportion; and thirdly, mixed powder subjected to ball milling is placed in a graphite mold to be hot-pressed and sintered or is placed in a steel mold to be pressed into a blank, and non-pressure compacting sintering is conducted in the reducing atmosphere. The honing oil stone prepared through the preparation method has the advantages of being high in strength and hardness, high in honing efficiency, high in self-sharpness, long in service life and the like.