Abstract: By altering the electrochemical properties of slag, the decarburization reaction of Fe³⁺-based slag with Fe-C droplet was studied. The results showed that a lot of free electrons and holes exist in the slag containing transition metal oxides (such as TiO₂ and Fe₂O₃). So electronic conduction in the slag increases. Finally, it led to the increment of the decarburization reaction rate between slag and Fe-C droplet, and mass fraction of carbon remaining in droplet decreases to a lower level.