The invention discloses a preparation method of tungsten-carbide-based non-bond cemented carbide. The preparation method includes providing a tungsten carbide composite powder precursor doped with active microelements, wherein the active microelements refer to one or more of lanthanum, cerium and yttrium; roasting the tungsten carbide composite powder precursor in a tubular furnace at the temperature of 650-850 DEG C and cooling to obtain tungsten carbide composite powder doped with the active microelements, subjecting the tungsten carbide composite powder to spark plasma sintering at the sintering temperature of 1600-1700 DEG C and at the sintering pressure of 30-50 MPa so as to obtain the tungsten-carbide-based non-bond cemented carbide. The preparation method has the advantages that through adoption of the tungsten carbide composite powder doped with the active microelements, owing to uniform doping of the active microelements, the sintering temperature of the tungsten-carbide-based non-bond cemented carbide is decreased greatly, and high compactness and excellent mechanical performance are achieved; experiment results show that the prepared tungsten-carbide-based non-bond cemented carbide is high in compactness and excellent in mechanical performance.