Avermectin-salinomycin waster is hard to be further biodegraded after treated by anaerobic-aerobiotic process, so Fenton oxidation process is studied for its advanced treatment. Influencing factors of pH, reaction time, H₂O₂ dosage and H₂O₂/Fe²⁺ on COD removal are investigated, respectively. When pH value is 3.0, the dosage of H₂O₂ is 1.5 mL/L, and the mole ratio of H₂O₂/Fe²⁺ is 5∶1, the effluent COD mass concentrations decreases from 224 to 64.3 mg/L, namely the COD removal efficiency reaches 71.3%.