The invention discloses a preparation method for Fe-Al-Mn-C alloy. The preparation method comprises the steps that the nanotechnology, the dynamic magnetic compaction, the microwave sintering technology and the powder metallurgy technology are utilized comprehensively, nanoscale Fe-Al-Mn-C composite powder bodies are prepared through a mechanical grinding method and are squeezed to be in a block shape, and Fe-Al-Mn-C alloying is achieved under the reduction protective atmosphere in the low temperature range. When sintering is conducted, powder oxidation is effectively reduced by using reduction gas, and the producing quantity of other oxide impurities is decreased; crystal grains of the Fe-Al-Mn-C alloy prepared through the nanotechnology are refined, and the corrosion resistance and the high-temperature oxidation resistance of the Fe-Al-Mn-C alloy are improved effectively; the plasticity of the obtained Fe-Al-Mn-C alloy is improved greatly by adding with traces of rare earth element cerium.