The invention relates to a novel dental niobium-silver alloy material and a preparation method thereof. The niobium-silver alloy material is composed of 60-99.95% of niobium and 0.05-40% of silver according to the molar percentage content. A silver powder and a niobium powder are mixed under an inert atmosphere and then are subjected to high-energy ball milling in a high-energy ball mill, the silver powder and the niobium powder are forced to be mixed and dissolved to form a single-phase solid solution, then the single-phase solid solution is sintered into the block niobium-silver dual-phase alloy material by using a spark plasma sintering technology. The silver-niobium alloy material is composed of nano-scale niobium grains and silver grains, has the grain size of 20-300 nm, has excellent biocompatibility and antibacterial properties, has the compressive strength reaching 1.0-1.8 GPa and the Vickers hardness reaching 3.0-6.5 GPa, also has good corrosion resistance and wear resistance, has the surface showing metallic luster, is a novel dental alloy, and has a good application prospect.