Abstract: To achieve standard⁃compliant reuse of leachate from a tailings pond, a combined process of A/O andmodified SBR was adopted. Based on biological denitrification theory and acclimation of functional microorganisms,process commissioning and system optimization were carried out to address issues such as sludge washout and disinte⁃gration in Sedimentation Tank No.2. The combined system achieved efficient removal of total cyanide, COD, and ammonianitrogen from the leachate. Results show that the effluent concentrations of COD, ammonia nitrogen, and total cyanideconsistently met the requirements of DB 21/1627— 2008 Integrated Wastewater Discharge Standard. This studyprovides technical reference for the compliant treatment and reuse of leachate from tailings ponds in the gold smeltingindustry.