Abstract: For a Tienriched reductive slag system of CaOSiO2TiOxM Al2O3,creating an optimum physical chemistry condition will selectively enrich TiO2 in perovskite at the drive of its chemical potential during slag's cooling.To investigate this physical chemistry behavior,two approaches were carried out.One was by oxidizing the slag at high temperatures and another was by adjusting the slag basicity.The physical chemical mechanism of selective enrichment was as following: 　　Oxidization of molten slag could change multivalent Ti compounds into TiO2 and increase the activity of TiO2 within the slag.TiO2 combined with CaO in the slag forming perovskite.The oxidation not only changed the compositions and structures of the slag phases but also caused majority of TiO2 migrating into perovskite.The increment of perovskite precipitated by oxidization could up to 30％ to 40％ of the precipitation in its original slag.It was found that raising the slag basicity could increase the activity of CaO in the slag that facilitated the selective precipitation of perovskite as well.Both approaches could promote the forward reaction of perovskite precipitation,TiO2＋CaO = CaTiO3(s),if slag basicity was adjusted up to 1.3 and this slag was oxidized sufficiently,about 80％ amount of TiO2 in slag could be collected in the form of perovskite.