Abstract: The iron tailings of magnetic separation in Qidashan mineral processing plant were used as raw materials to prepare the iron tailings-based porous substrate using a mold pressing and sintering method by adding pore-making agent, and then the application of the obtained substrate in the synthesis of Co₃O₄ nanomaterials was discussed. Based on the analysis results of the particle size and composition of iron tailings, the effect of the dosage of polymethyl methacrylate (PMMA) microspheres on the bulk density and porosity of iron tailings-based porous substrate was investigated. By scanning electron microscopy (SEM) observation, the pore structure of the porous substrate was optimal when PMMA microspheres of 10% were added into iron tailings. Co₃O₄ nanowires were prepared on the porous substrate by a hydrothermal method using Co(NO₃)₂·6H₂O as cobalt source, urea as alkali source and sucrose as template agent. The influence of hydrothermal time on the morphology of Co₃O₄ nanowires was also investigated. The results illustrated that Co₃O₄ nanowires obtained at 160 ℃ for 6 h showed high length-to-diameter ratio and uniform morphology, which were suitable for acting as the potential raw materials of nanosensors.