Heterogeneous catalytic ozonation was applied to the treatment of coal chemical industry wastewater secondary effluent. Activated carbon-supported copper and manganese oxide were used as catalysts to assist ozone in degrading COD and NH₃-N of secondary effluent. The results indicated that the presence of catalysts significantly elevated the removal efficiency of ozone on COD and NH₃-N, as compared to the single ozone oxidation. The final effluent removal efficiency of COD and NH₃-N were 60％-72％ and 30％-35％ respectively, the average concentration of COD and NH₃-N was lower than 60 and 15 mg／L, and met Wastewater Discharge Standard (GB 18918—2002). The catalytic activity was restricted in acidic conditions and promoted in alkali conditions, however, catalysts improved degradation efficiency regardless of acid-base conditions as compared to the single ozone oxidation. The final effluent biodegradability was significantly improved, and no secondary pollution in the receiving water was produced.