Abstract: The Fenton method was employed to investigate the treatment of the refractory wastewater from a coating production.The results demonstrated that the COD removal efficiency of 93.92% was achieved when the ratio of n（H₂O₂）:n（FeSO₄） was 1.4 and the ratio of n（H₂O₂）:n（COD） was 10.5.By maintaining a fixed n（H₂O₂）:n（FeSO₄） ratio between 1.2～1.4 and an added n（H₂O₂）:n（COD）ratio between 3.1～10.5,the COD removal rate increased from 46.06% to 93.92%.However,adjusting the FeSO₄ dosage according to the n（H₂O₂）:n（FeSO₄） ratio ranging from 1.2 to 2.8 had no significant impact on COD removal when using respective ratios of n（H₂O₂）:n（COD） at 3.1 and 10.5 respectively.Furthermore,employing a two-stage Fenton also improved COD removal efficiency with significantly lower FeSO₄ requirements compared to the primary Fenton.