Abstract: The characteristics of the chemical compositions and mineralogical phases of the converter slag Panzhihua Iron and Steel Co. are described.The phase constituents of the slag added with manganese ore or spar and quartz sand are analysed.It is shown that different flux results in different mineralogical phases in dephosphorization and desulphurization. An investigation ha:been made into the impact of different flux on the converter lining,concluding that the slag added with manganese ore is viscous and protective to the lining.while slags added with quartz sand and spar are free running slag and make the lining worn.