The structure of FeO–SiO₂–V₂O₃ slags with compositions of (1-x)(1.5FeO·SiO₂)·xV₂O₃ (x=0–20% mole fraction) was investigated in the molten and quenched states by using molecular dynamics (MD) simulations and Fourier transform infrared (FT-IR) spectroscopy. An empirical potential for the multi-component system has been developed in this work for performing MD simulations. The local atomic structures and the micro-heterogeneity in the molten slag have been systematically investigated using MD simulations. The bond length of V–O varies from 1.92 to 1.96 Å and the averaged coordination number of V (CN_V–O) increases from 4.50 to 4.96 with the addition of V₂O₃. The simulation results revealed that the average Si–O–Si bond angle and the degree of polymerization both decrease with increasing amount of V₂O₃, implying that V₂O₃ may behave as a network-modifying basic oxide in the FeO–SiO₂–V₂O₃ system. This was further confirmed by the FT-IR spectrum analysis, which shows that the silicate network dissociates with the presence of V₂O₃.