Abstract: The removal efficiency of dissolved organic matter (DOM) in secondary effluent by Al₂O₃ and Fe(III)-Al₂O₃ was compared, and the SEM and XRD were used to analyse the changes in structure and composition of Al₂O₃ and Fe(III)-Al₂O₃. While the UV parameters and three-dimensional fluorescence spectroscopy were used to characterize the changes of DOM. The results showed that the removal efficiency of Al₂O₃ was improved remarkably after modification. When the sintering temperature was 150 ℃ and the dosage of Fe(III)-Al₂O₃ was 30 g, the removal rate of chroma was 93.8%. While the removal rate of dissolved organic carbon (DOC) was 38.7%. Fe(III)-Al₂O₃ had many pore structures and loaded with iron hydrous oxides on the surface, which had stronger adsorption capacity for aromatic compounds with high molecular weight and oxygen-containing functional groups. It selectively adsorbed humic-like and fulvic-like substances, which could provide a targeted advanced treatment technology for secondary effluent in tannery wastewater combined with advanced oxidation processes.