Abstract: The morphology and chemical composition of inclusions were analyzed with experiment in molten steel deoxidized by Al after Ti deoxidation;the structures and mechanical properties of this steel were also studied.It is shown that the type of inclusions in the steel is mainly titanium oxide when the mass fraction of aluminum is 0.015%.Titanium oxide could promote the formation of acicular ferrite which refines the microstructure of the steel.Compared with the steel without Al deoxidation,the impact toughness of the steel deoxidized by Al increases by 33%,proving the feasibility of final aluminum deoxidation.