The invention discloses a gel injection molding method for high-gravity alloy, which belongs to the field of powder metallurgy. The method is characterized by comprising the following steps: firstly, weighing metal powder of tungsten, nickel, iron, copper, molybdenum, and the like used as raw materials with the average particle size of 1 to 100 micros according to a proportion, and ball-milling the metal powder for 1 to 20 hours to mix the metal powder evenly; then, mixing a monomer and a cross linker in a mass ratio of (1-250): 1, and dissolving the mixture into deionized water to obtain 10 to 55 percent solution; adding the evenly-mixed alloy powder and dispersant accounting for 0.01 to 5 percent of the volume of the alloy powder into the solution, ball-milling the mixture for 2 to 10 hours to form slurry with good fluidity, and exhausting the air for 5 to 60 minutes; and adding 0.02 to 2 percent of catalyst and initiator accounting for 0.02 to 5 percent of the mass of the monomer into the slurry, stirring the mixture evenly and slowing injecting the mixture into a die after exhausting, solidifying the mixture for 20 to 180 minutes at the temperature of between 20 and 70 DEG C, then releasing the solidified mixture from the die, drying the mixture for 30 to 120 hours in vacuum, and then sintering the mixture for 0.5 to 3 hours at the temperature of between 1,100 and 1,550 DEG C to obtain high-gravity alloy workpieces. The molded alloy workpieces have consistent performance, small weight dispersion degree, high size precision and high yield. The method does not need complex equipment and special degreasing process, and has simple process and low production cost.