The invention relates to a preparation method of a high specific gravity tungsten alloy material and a nano crystal block. In the present invention, firstly, the tungsten, nickel, iron and cobalt powders are proportioned according to the following mass percentages: W93.0%, Ni3.5-4.5%, Fe1.5-2.0%, Co1.0-1.5%, and the rest are Trace impurities; after powder mixing, high-energy ball milling is carried out until the tungsten phase grains in the ball-milled powder are refined to the nanometer level, and then square wave DC pulse-constant current is used for rapid sintering, sintering pressure: 40MPa~50MPa, sintering time: 3 ~8 minutes, the nanocrystalline block high specific gravity tungsten alloy material can be obtained after sintering. The high-specific-gravity tungsten alloy of the invention has a reasonable formula, can help to obtain nanocrystalline sintered materials, and can improve the comprehensive mechanical properties of sintered materials. The invention obviously lowers the requirements for equipment, thereby reducing the cost, and is particularly beneficial to the localization of the production of bulk nanocrystalline high-density tungsten alloy materials.