The invention discloses a preparation method of a large-size high-performance tungsten alloy material. The preparation method comprises the following steps: alloy powder is uniformly mixed to obtain amixture, the mixture is formed through cold isostatic pressing, the formed mixture is subjected to circulated sintering densification, a sintered workpiece is subjected to rough machining and splicing surface treatment, the splicing technology is carried out in an induction sintering furnace, and the spliced large-size tungsten alloy product is subjected to vaccum thermal treatment and finish machining to obtain a finished product. According to the preparation method, the technology is simple, the cost is low, the mechanical property of all parts of a product is ensured to be stable; the material composition is ensured to be uniform, the difficulty of the manufacturing technology is lowered, the material utilization ratio is increased, and the production cost is reduced. The preparation method is also suitable for splicing of tungsten alloy pieces with different densities and compositions; variable density and variable performance can be realized on one product; the requirement that the mechanical property of different parts of a specified product is different is met; the requirement to the equipment safeguarding capacity is lowered, the rate of finished products is increased, theproduction efficiency is improved, the blank of China in the field is filled, and the market application prospect is broad.