The invention discloses a high-corrosion-resistance iron-based amorphous alloy material and a preparation method thereof. The iron-based amorphous alloy material has high corrosion resistance, high amorphous forming capability and excellent magnetic properties. The chemical formula of the alloy material is FeaCobSicBdPeCfMog, wherein a, b, c, d, e, f and g are the percent contents of various corresponding component atoms by mass respectively, a is greater than or equal to 60 and less than or equal to 80, b is greater than or equal to 5 and less than or equal to 12, c is greater than or equal to 5 and less than or equal to 10, d is greater than or equal to 7 and less than or equal to 13, e is greater than or equal to 3 and less than or equal to 8, f is greater than or equal to 1 and less than or equal to 4 and g is greater than or equal to 0 and less than or equal to 7 with the sum of a, b, c, d, e, f and g being 100. The preparation method of the alloy material comprises the steps of preparing raw materials, melting, cooling to form alloy ingots, removing impurities on the surfaces of alloy ingots, preparing iron-based amorphous alloy thin sheets or iron-based amorphous alloy bars and carrying out stress relief annealing. According to the alloy material and the preparation method thereof disclosed by the invention, the contents of the components in the FeCoSiBPCMo alloy system are controlled to be close to an eutectic point, a closely packed structure is easily formed, the amorphous forming capability is achieved, and the high corrosion resistance and excellent magnetic properties are simultaneously obtained; therefore, the iron-based amorphous alloy material can be used as an electromagnetic device in harsh environments.