The invention relates to a high-toughness silicon carbide ceramic and a preparation method thereof. The high-toughness silicon carbide ceramic comprises 3-5% of a toughening agent titanium carbide, 1-4% of a sintering aid, and the balance silicon carbide and inevitable impurities, wherein the sintering aid comprises carbon and boron carbide according to a mass percentage ratio of 1:(0.6-8). The preparation method of the ceramic comprises the following steps: uniformly mixing silicon carbide with the toughening agent titanium carbide and the sintering aid comprising carbon and boron carbide, adding the obtained mixture into a ball mill, adding water-soluble resin and distilled water, carrying out ball milling, drying, adding the dried mixture into a steel mold, carrying out compression molding, sintering the molded mixture in a vacuum furnace, and carrying out surface grinding to prepare the high-toughness silicon carbide ceramic. The addition of the toughening agent titanium carbide into a silicon carbide matrix makes the fracture mode of the silicon carbide ceramic change from intergranular fracture to transgranular fracture, and improves energy required by the transgranular and intergranular fracture in order to enhance the flexural strength.