Abstract: Based on the ion and molecule coexistence theory,we calculated the activity coefficient of V₂O₃ in the vanadium removing slag V₂O₃-SiO₂-TiO₂-Cr₂O₃-MgO-MnO-FeO,the influence of vanadium composition、temperature on the activity coefficient of V₂O₃ has been investigated,the activity coefficient of V₂O₃ is between 0.5×10^-6 and 9.0×10^-6.Through studying the vanadium-carbon reaction equilibrium,the oxidation transformation temperature of vanadium and carbon is 1 380℃,which is the temperature control during blowing.The vanadium removal in combination blowing converter process was simulated by experiment in 500 kg intermediate frequency induction furnace with top and bottom blowing function,the experiment results shows:at the end point of blowing the average vanadium content in hot metal was 0.06%,vanadium oxidation rate was 95%.In addition,bottom blowing can accelerate vanadium oxidation,shorten 3 minutes oxygen supply time.