Abstract: Reaction mechanism between CO₂ and molten pool elements at the steelmaking temperature was researched. The related thermodynamics and kinetics were analyzed. The industrial test by top and bottom blowing CO₂ was carried out in a 30 t converter. It is discovered that the amounts of smoke dust and T-Fe are reduced by 11.15% and 12.98% on average. Iron loss of slag is lowered by 3.10%,and the contents of nitrogen and phosphorus are decreased by 50% and 23.33% respectively. The new process is absolutely feasible,which will provide a new method for saving energy consumption in BOF steelmaking process.