<p>Electrical conductivity is an important physical property parameter of the electroslag remelting slag system. Alternating current (AC) four-probe method based on electrochemical methods was used to measure the electrical conductivity of CaF₂–CaO–Al₂O₃–SiO₂–MgO–CeO₂ slag systems containing CeO₂. The influence of slag composition, temperature and the ratio of <i>ω</i>(CaO)/<i>ω</i>(Al₂O₃) on the electrical conductivity of slag systems containing CeO₂ was studied. Experimental results show that the conductivity of the slag first increases and then decreases as the content of CeO₂ in the slag increases on a scale from 0 to 12 pct. As CeO₂ content increase from 0 to 6 pct, Ce₂O₃ and Al₂O₃ will produce CeAlO₃, the high melting point of CeAlO₃ results in altered of electrical conductivity of slag system. With the increase of CeO₂ content from 6 to 9 pct, Ce₂O₃ and SiO₂ will produce CeSiO₄, which leads to a reduction in the silicate network structure and thus a decrease in the conductivity of slag system.</p>