In the current study, laboratory experiments of the slag‐steel reaction are performed to investigate the effect of CaF2 contents in the refining slag on the inclusion absorption of the bearing steel. The increase of the CaO/Al2O3 ratio effectively enhances the absorption of inclusions by slag. The increase of the CaO/Al2O3 ratio enhances the driving force of the inclusion dissolution and lowers the slag viscosity. It is noted that the excessive CaO/Al2O3 ratio led to the formation of solid phases in the slag, lowering the absorption effect of slag. The appropriate addition of CaF2 in the slag is helpful to remove inclusions while aggravating the corrosion of MgO crucibles. The addition of CaF2 mainly reduces the viscosity and melting temperature of slag. The inclusion removal factor is proposed to effectively evaluate the inclusion removal rate in steel during slag steel reaction. As a result, the most recommended composition of slags is 7% CaF2; the CaO/Al2O3 ratio is 2.0.