The invention discloses a preparation method for ultra-fine grain cemented carbide based on tungsten carbide. The method comprises the steps that nano-scale WC-Co mixed powder is prepared through ultrasonic concussion, the mixed powder is dried, ground, poured into a die after sieving and then subjected to prepressing, finally, in the vacuum environment, a spark plasma sintering technique is adopted, the temperature is continuously increased to 1300+/-20 DEG C at the temperature increase speed of 100+/-20 DEG C/min, the pressure is controlled to be 30+/-2 MPa, and the ultra-fine grain cementedcarbide based on tungsten carbide is obtained. The ultrasonic concussion method and the spark plasma sintering technique are combined, the prepared ultra-fine grain cemented carbide based on tungstencarbide is high in hardness and good in toughness, meanwhile, the production process is greatly simplified, and the production efficiency is improved.