An iron-based superalloy for high temperature 700° C. with coherent precipitation of cuboidal B2 nanoparticles, belongs to the field of heat-resistant stainless steel, including Fe, Cr, Ni, Al, Mo, W, Zr, B elements. C, Si, Mn, S, P, O, N are impurity elements. The weight percent (wt. %) of its alloy composition is Cr: 10.0˜12.0, Ni: 13.0˜15.0, Al: 6.0˜7.0, Mo: 2.0˜3.0, W: 0.3˜0.7, Zr: 0.03˜0.05, B: 0.004˜0.007, C≤0.02, Si≤0.20, Mn≤0.20, S≤0.01, P≤0.02, O≤0.005, N≤0.02, Fe: balance; and the atomic percent ratio of Zr/B is 1:1, the atomic percent ratio of Cr/(Mo+W) is 8:1, and the atomic percent ratio of Mo/W is 8:1. The coherent precipitation of cuboidal B2 nanoparticles in ferritic matrix through the alloy composition design.