The iron-containing rotary kiln tailings slag (referred to as“iron-containing kiln slag”) has a high iron grade and a metallization rate， and has potential for high-value resource utilization.Based on the properties of iron-containing kiln slag，in the study of this paper the reductive melting-separation test was conducted. Phase diagrams of ternary slag systems under different basicities were drawn with FactSage software to systematically study the influence rule of melting-separation temperature，basicity，and carbon-oxygen ratio on the melting-separation effect，iron particle quality，and iron recovery rate.The results indicate that the increasing the melting-separation temperature facilitates the effective separation of slag and iron and enhances the iron recovery rate;the basicity significantly influences the melting-separation result，and the effect on iron recovery rate shows a tendency of initially increasing and then decreasing.The effect of the carbon-oxygen ratio on the melting effect shows that the iron particle quality and iron recovery first decrease and then increase.Under conditions of a melting-separation temperature of 1 550 ℃，basicity of iron-containing kiln slag of 1.0，and carbon-oxygen ratio of 1.4， the mass of iron particles separated from 100 g of sample was 43.36 g， achieving an iron recovery rate of 94%.The findings of this study can provide a theoretical basis for the high-value resource utilization of iron-containing kiln slag.