The invention provides a nickel-iron based nitrogen-containing alloy magnetostrictive material and a preparation method thereof. The magnetostrictive material may be produced by the following steps: reducing nickel, iron and oxygen in a mixed atmosphere of H2/N2 at 800-1000 DEG C for 2-4h to obtain a single-phase nickel-iron alloy; and subsequently, carrying out annealing in an atmosphere of NH3 at 500-1000 DEG C for 2h. The present invention also includes the preparation method of the nickel-iron based nitrogen-containing alloy magnetostrictive material. The NFN material of the present invention has a greater magnetostrictive coefficient and excellent resistance to acid, alkali and salt corrosions, and further is simple in preparation process, low in price, and suitable for either industrial production or use in high-corrosion environments and high-frequency fields. Experiments prove that, compared with a nickel-iron alloy (NF), the NFN material of the present invention has no obvious change after being corroded for 24h in an acidic, alkaline or salty solution, and has excellent corrosion resistance, and therefore, the application range thereof in corrosive environments is expanded; meanwhile, the magnetostrictive coefficient of the NFN is higher than that of the NF and may be up to 271ppm, and therefore, the application range of the NFN in the high-frequency fields also can be expanded.