The liquid phase formation during iron ore sintering process with different different MgO/Al₂O₃ ratio was simulated and calculated by FactSage software, and the laws of effect of MgO/Al₂O₃ ratio on the characteristic temperature of liquid phase formation for the kaolinite and gibbsite type Al₂O₃ mixture were studied through experiments. The results show that the sintering liquid phase volume increases with the increase of temperature. With MgO/Al₂O₃ ratio increasing from 0.5 to 1.8, the effective initial liquid phase formation temperature of sintering mixture decreases, the effective liquid phase formation ending temperature increases slightly, and the complete melting temperature range increases. Appropriate MgO/Al₂O₃ ratio is favorable for improving the amount of sintering liquid phase formation.