Abstract: The molecular dynamics method was used to simulate the whole process for noncrystalline/nanocrystalline Fe₇₅Cr_12.5Mo_12.5 alloy. The amorphous/nanocrystalline structure of Fe₇₅Cr_12.5Mo_12.5 alloy was obtained through the dynamic relaxation,quenching,and annealing. Structural parameters of Fe₇₅Cr_12.5Mo_12.5 alloy in different stages were analyzed through radial distribution function(RDF) and X-ray diffraction(XRD).Resultsshow that Fe₇₅Cr_12.5Mo_12.5 alloy has amorphous and nanocrystalline formation ability,and can further increase by adding other nonmetallic element. Molecular dynamics simulation technique will provide a theoretical basis for composition and process of Fe-based amorphous/nanocrystalline alloy.