Abstract: Experiments were carried out in laboratory to investigate the effect of Al content on the Ti/Al inclusion in 430 stainless steel containing titanium.It was found that the size of the inclusions increased with the Al content increasing.And some solid solution of Ti₂O₃ and Al₂O₃ were observed in high Al content's sample.The disregistry between Ti₂O₃ and Al₂O₃ was calculated.It was proved that Ti₂O₃ easily attached to Al₂O₃ to form nuclei.In order to prevent forming larger inclusion,a thermodynamic study was undertaken to analyze the effect of Al on forming titanium oxides.The equilibrated relations between Al-Ti-O was calculated and the optimal ratio of[Ti]/[Al] was put forward.