In the contemporary global context of carbon neutrality, it is imperative for the ironmaking industry to progressively transition away from the use of fossil fuels. The traditional blast furnace-basic oxygen furnace (BF-BOF) route, which remains the dominant pathway in steel production, is significantly reliant on coal. As a lower-carbon alternative, the direct reduced iron-electric arc furnace (DRI-EAF) route has been increasingly adopted. However, the EAF is highly sensitive to the level of impurities in DRI, which limits its applicability for processing low- to medium-grade iron ores. In contrast, the electric smelting furnace (ESF) exhibits greater flexibility in raw material input and furnace composition adjustments. Owing to its capability for continuous and stable production, the ESF has been widely used in the production of ferroalloys and nonferrous metals and demonstrates great potential for future large-scale, low-carbon ironmaking. In the DRI-ESF route, BF grade ores can first be reduced using natural gas or hydrogen in shaft furnaces or fluidised beds to produce DRI, which is subsequently smelted in ESF using electricity. Currently, no commercial-scale ESF process operates using BF grade DRI. Therefore, a comprehensive understanding of the DRI behaviour in the ESF process, especially the properties of the ESF slag where DRI melting and smelting occur, is imperative for ESF design, process optimisation and control. Among these properties, the electrical conductivity of slag is of particular importance, as heat in ESF is generated through resistive heating of the slag, thereby directly influencing DRI melting and reaction behaviour. In this study, the electrical conductivity of DRI smelting slags was systematically investigated as a function of slag composition and temperature using the four-electrode method. The experimental samples were synthesised from CaO, SiO2, MgO, Al2O3, and ‘FeO’. An orthogonal experimental design was employed to evaluate the effects of compositional variations and temperature on slag electrical conductivity. The underlying mechanisms governing slag electrical conductivity are discussed through correlations between the electrical conductivity, slag composition and temperature.