Nano-ribbons of (Fe,Ni) 3 (P,B) intermetallic compound have been prepared by a so-called selective etching method from the precursor Fe 40 Ni 40 P 14 B 6 alloys. These precursors, with a eutectic structure constituting of (Fe,Ni) 3 (P,B) phase and γ-(Fe,Ni) phase, were prepared in a rod shape by the rapid quenching method. Then, the γ-(Fe,Ni) phase was dissolved off from the eutectic structure through selective etching with aqua regia, resulting in nano-ribbons, with about 10–50nm thickness, 300–1000nm width and about 10μm or more length, having been obtained under the action of etching and polishing effects. Based on the experimental results, the possible evolution process of (Fe,Ni) 3 (P,B) nano-ribbons from eutectic structures was proposed. The present result shows that the selective etching method is an easy and effective approach for preparing metallic nano-ribbons.