The invention relates to a gradient composite ceramic tool material TiB2/TiC/WC and a preparation method thereof. The gradient composite ceramic tool material is formed by taking TiB2-20wt%TiC as a base body, adding a reinforced phase WC in a gradient mode and taking Ni and Mo as sintering aids through hot-pressing and sintering. The gradient composite ceramic tool material has components with gradient layer structures which are symmetrical with respect to a middle layer; and the WC content is increased layer by layer from the middle layer to the surface layer. When relatively high fracture toughness and relatively high bending strength of the material are kept, and thermal expansion coefficient difference at each layer is utilized to generate pressure stress on the surface layer to increase surface-layer hardness; and the obtained gradient composite ceramic tool material can be used for manufacturing a high-speed cutting tool material, a high-temperature wear-resisting structural partand the like.