Abstract: The sulfur partition ratios between high basicity and high alumina CaO-Al₂O₃-SiO₂-TiO₂-MgO-Na₂O slags with hot iron were experimental determined at 1773K, the desulfurization property of the slag was studied. The regression equation was established using the partial least squares regression analysis, which can well predict the sulfur partition ratio. The effects of basicity (CaO/SiO₂), MgO, TiO₂, Al₂O₃ and Na₂O on the sulfur partition ratio were analyzed with the regression equation. The results indicate that when the basicity is greater than 2.9, the sulfur partition ratios are all above 140, which indicate that the CaO-Al₂O₃-SiO₂-TiO₂-MgO-Na₂O complex slag has stronger desulfurization ability. In experimental composition ranges, the sulfur partition ratio increase with basicity(m_CaO/m_SiO2) increasing. When the basicity is fixed, the effect of MgO on the sulfur partition ratio is not obvious. The addition of the TiO₂ and Al₂O₃ content decrease the sulfur partition ratio, especially the effect of Al₂O₃is very obvious. the sulfur partition ratio increase with Na₂O content increasing, and the small increase of Na₂O content can improve the desulfurization ability of the slags.