The invention relates to the technical field of electrothermal alloy materials, in particular to a machining method of an iron-chromium-aluminum high-resistance electrothermal alloy. According to the technical scheme, the method comprises the following step of 1) weighing corresponding parts of chromium, aluminum, iron, yttrium, titanium, rhenium, cobalt and rare earth elements of lanthanum and yttrium by weight, fully mixing, and fully stirring for 10 minutes at the temperature of 80-90 DEG C, wherein the components specifically comprise 26.5 parts of chromium, 17.2 parts of aluminum, 33.5 parts of iron, 28.1 parts of yttrium, 1.44 parts of titanium, 8.25 parts of rhenium, 0.6 to 1.3 parts of cobalt, 1.5 parts of silicon, 6.8 parts of manganese, and 0.3-0.4 part of rare earth elements of lanthanum and yttrium. The machining method has the advantages that the oxidation resistance, the heat resistance, the corrosion resistance and the like of the produced iron-chromium-aluminum high-resistance electrothermal alloy can be ensured to be more reliable, the use requirements in a wider use environment can be met, and the overall cost in the production process is ensured to be lower.