The invention discloses a nano-particle modified titanium-carbide-based hard alloy and a preparation method thereof. The titanium-carbide-based hard alloy consists of the following raw materials in percentages by mass: 2-8% of nano titanium carbide (TiC), 45-55% of titanium carbide (TiC), 15-20% of tungsten carbide (WC), 15-20% of nickel (Ni), 6-10% of molybdenum, 1-2% of tungsten (W), 1-2% of chromium carbide (Cr3C2), and 0.5-1.5% of carbon powder (C). The preparation method comprises the following steps: (1) preparing a mixture; (2) ball-milling, filtering, drying, mixing with glue, and granulating to obtain mixture particles with uniform size; and (3) forming by compression, sintering under vacuum, and cooling to room temperature to obtain a finished product. The hard alloy material prepared by the invention is high in hardness, good in wear resistance and corrosion resistance, low in porosity and high in cost performance, and can be used for finish machining of continuous cutting of low-carbon steel.