The invention discloses a special total synthesis grinding fluid for a hard alloy and a preparation method of the grinding fluid; the preparation method comprises the following steps of: mixing efficient special component, extreme-pressure lubricant and water for 10min to 1 hour at 30 DEG C to 80 DEG C, so as to obtain a mixture component A; mixing pH (potential of hydrogen) stabilizer, antirust agent and water for 10min to 1 hour at 30 DEG C to 80 DEG C, so as to obtain a mixture component B; mixing surfactant and coupling agent at normal temperature and under normal pressure, so as to obtain a mixture component C; and adding the three groups of mixture components A, B and C into a reaction kettle, mixing for 10min to 1 hour at 30 DEG C to 80 DEG C, so as to obtain a product. The grinding fluid prepared by the preparation method disclosed by the invention can effectively inhibiting cobalt leaching, has an excellent lubricating property, cooling property, antirust property and cleaning property, and is long in service life, is green and environment-friendly.