Abstract: The electroslag remelting of F55 duplex stainless steel is investigated.Resultsshow that the oxygen content increases after the electroslag remelting of the F55 electrode. The inclusions in the steel are mainly Al2O3 by SEM analysis. By optimizing the ESR process, using the slag of CaF2-CaO-Al2O3-MgO-SiO2 and adding SiCa and Al to deoxidize, the Al2O3 inclusions become deformed and the melting point becomes low, so the inclusion is easy to be removed from the steel, realizing the control the inclusions in the process of electroslag remelting of F55.