The invention discloses a ZrB2-SiC eutectic composite ceramic directional solidification preparation method. A laser beam of a high-energy CO2 laser device serves as a heating source, ZrB2-SiC composite ceramics of eutectic components are rapidly zone-melted by small light spots, and a melting zone is stabilized by accurately controlling laser power and scanning rate, rapidly cooled and continuously solidified to obtain an anisotropic ZrB2-SiC eutectic composite ceramic with a refined structure and phase distribution uniformity. The microstructure of the obtained ZrB2-SiC eutectic composite ceramic is a labyrinth laminated eutectic structure. Compared with a ZrB2-SiC composite ceramic obtained by conventional sintering preparation technology, the ZrB2-SiC eutectic composite ceramic has the advantages that two phases of the structure are firmly combined, the structure is refined, a phase interface is clean, intergranular amorphous phases are avoided, and mechanical property can be further improved.