The invention discloses a hafnium boride-silicon carbide-graphite-tantalum silicide composite ceramic heating body and a preparation method thereof. The preparation method comprises the following steps that hafnium boride, silicon carbide, graphite and tantalum silicide mixed powder is prepared from, by volume, 60%-83% of hafnium boride, 10%-20% of silicon carbide, 5%-15% of graphite and 2%-5% of tantalum silicide to serve as a ball milling material, and the ball milling material and absolute ethyl alcohol are added into a ball milling machine according to the volume ratio of 1:(1-2) to be ball-milled; mixed slurry is dried by adopting a rotary evaporator; the mixed powder is contained in a graphite mold, and the graphite mold is put into a vacuum hot-pressing furnace to be subjected to hot-pressing sintering. The heating body prepared by taking hafnium boride, silicon carbide, graphite and tantalum silicide as the main raw materials is high in compactness and using temperature, capable of achieving the highest using temperature of 2,500 DEG C in an oxidative environment, excellent in oxidation resistance and mechanical strength, not prone to fracture in the installing and using process, simple in process, short in production cycle and suitable for industrialized production.