Abstract: The Oxidized relation between Mn and P in pretreatment of hot metal containing low Si, high Mn and mid P by using lime-based flux was investigated. The results show that when﹝%Mn﹞ is above 0.32, Mn is more preferential oxidized than P, and when﹝%Mn﹞is low 0.32, the result is contrary to one above mentioned at 1573-1623K. The Mn content which is low 0.3% in hot metal is necessary in order to obtain the sufficient dephosphorization.