The strength and plasticity of Fe39Ni39B12.82Si2.75Nb2.3P4.13 bulk metallic glass(BMG)are improved simul-taneously by modulating atomic-scale structure through fluxing treatment.The compression strength increases from 3074 to 4220 MPa,and the plastic strain is enlarged from 10.7% to more than 50%.The increased mechanical properties of the fluxed FeNiBSiNbP BMG originate from the optimization of atomic-scale structure.More icosahedral-like clusters(ILCs)and crystal-like clusters(CLCs)are found in this FeNi-based BMG with fluxing treatment,and the ILCs are usually surrounded by CLCs.Furthermore,phase separation and a sandwich-like heterogeneous structure of SB are also observed during deforma-tion,indicating the multiscale deformation mechanism and a stable shear-band evolution.The unique"ILC surrounded by CLCs"structure and phase separation lead to a stable plastic deformation process with strong interactions of multiple shear bands,thereby the improved plasticity and strength.This work provides useful guidelines to develop strong and plastic Fe-based BMGs from a structural aspect.