Abstract: The phases,size distribution and morphology of inclusions as well as the microstructure of low carbon steel which is complex deoxidized by Al-Ti-Mg were investigated by technically deoxidizing pure iron with Fe-50%Ti,Ni-16.7%Mg and Fe-70.74%Si.The experimental results show that in comparison with non-Ti-treated samples the total number of inclusions in the Ti-treated steel increases by 400 mm^-2,meanwhile the size of inclusions decreases obviously.Comparing with Mg deoxidizing,the total number of inclusions in the Ti-Mg complex deoxidized steel increases by 200 mm^-2.There is a large number of acicular ferrite in austenite grains after being Ti-treated.The distribution of acicular ferrite is the most uniform and no polygon ferrite was observed in the Al-Ti-Mg complex deoxidized steel.