The invention relates to a nonmagnetic hard alloy material and a preparation method thereof. The alloy comprises (wt %) tungsten carbide 75-90, nickel powder 8-20, chromium carbide 0.5-3.0, and vanadium carbide 0.3-2.5. The preparation method comprises compounding, wet grinding, drying, pressing, sintering and checking, wherein in the wet grinding step, a nonmagnetic alloy lining board wet grinder is used, alcohol or acetone is added as grinding medium, nonmagnetic hard alloy balls is used as grinding material, the ratio of grinding medium to material is 5:1, the solid-to-liquid ratio is 350ml/Kg, and the wet grinding time is 48-56 hours; and pressure sintering is adopted. In the inventive nonmagnetic hard alloy material, fine-particle tungsten carbide powder (1.0-1.5 mum) is used as hard phase, so as to improve the hardness and abrasion resistance of the alloy. The nickel is used as binder, and a small amount of chromium carbide and vanadium carbide are added as tungsten carbide grain growth inhibitor, so as to refine tungsten carbide crystal grains, and further improve the hardness and abrasion resistance of the alloy. The pressure sintering technique accelerates densification speed during sintering process, effectively reduces porosity of the alloy, and remarkably improves the strength of the alloy.