The invention relates to a nickel-based alloy anvil for forging square and flat steels, which belongs to auxiliary facilities for metallurgical production. The nickel-based alloy anvil consists of a nickel-based alloy layer and a surfacing layer. The percentages by weight of the chemical components of the nickel-based alloy layer are as follow: C: 0.50 to 0.60, Si: 0.10 to 0.40, Mn: 0.65 to 0.95, P: 0.030 or more, S: 0.030 or more, Cr: 1.00 to 1.30, Mo: 0.45 to 0.55, Ni: 1.50 to 1.80, V: 0.07 to 0.12 and the balance of iron and inevitable impurities. The nickel-based alloy anvil is characterized in that a preparation method of the nickel-based alloy anvil includes the following steps: a pit is dug in the top surface of a nickel-based alloy anvil; the nickel-based alloy anvil is heated to 350 DEG C, and as the temperature of 350 DEG C is kept, a Ni847 welding rod is used for performing three times of surfacing in the pit; after surfacing is complete, the anvil is put into an annealing furnace and heated to 550 DEG C, and is treated by heat under constant temperature for 24 hours; the power is cut off, and the anvil is naturally cooled in the furnace for 10 to 12 hours. The service life of the nickel-based alloy anvil is long.