The invention discloses a preparation method for a nickel-based superalloy for an exhaust valve. The alloy consists of the following components in percentage by weight: 0.10 to 0.14 percent of C, 3.5 to 4.5 percent of Al, 1.5 to 2.5 percent of W, 2.0 to 4.0 percent of Mo, 13.5 to 15.5 percent of Cr, 0.4 to 0.6 percent of V, 0.10 to 0.20 percent of Zr, 0.5 to 1.5 percent of Nb, 8.0 to 12.0 percent of Fe, 2.5 to 3.5 percent of Ta, less than or equal to 0.20 percent of Cu, less than or equal to 0.8 percent of Mn, less than or equal to 0.020 percent of P, less than or equal to 0.015 percent of S, less than or equal to 0.3 percent of Si and the balance of Ni and inevitable impurities. The preparation method comprises the following steps of: (1) smelting the raw materials according to the proportions at smelting temperature of 1,570 to 1,600 DEG C in a medium-frequency induction furnace, and refining a product for 0.5 to 1 hour at refining temperature of 1,620 to 1,640 DEG C; (2) regulating pouring temperature into about 1,510 to 1,530 DEG C for pouring; and (3) performing heat treatment, heating the refined product to 1,240 to 1,260 DEG C, preserving heat for 3 to 5 hours, air-cooling the product to room temperature, heating the product to 1,150 to 1,170 DEG C, preserving the heat for 1 to 3 hours, heating the product to 900 to 920 DEG C, and preserving the heat for 18 to 24 hours.