For the iron-based nanocrystalline core with the grade of 1K107D, the molten alloy is rapidly quenched into the amorphous strip through a rapid solidification process, and nanocrystalline grains are precipitated on the amorphous matrix through heat treatment in the later period with such excellent characteristics as high saturated magnetic induction intensity, high magnetic permeability, low coercivity, low loss, good stability, high strength and toughness, and wear and corrosion resistance. As the nanocrystalline alloy with the best cost performance among metal soft magnetic materials, they can replace the silicon steel, permalloy and ferrite to be an ideal material for medium- and high-frequency transformers, transformers and inductive components.