The effect of activated carbon dosage, chlorine dioxide dosage, pH value and reaction time on the paranitrobenzoic acid wastewater treatment on chlorine dioxide (ClO2 ) and activated carbon (AC) catalysis-oxidation technology were analyzed, and the efficiencies of the process to remove COD and increase biodegradation capacity (BOD5/COD ratio) were also examined under the optimum conditions as the pretreatment method for paranitrobenzoic acid wastewater with high-concentration. The result showed that the COD removal efficiency of the ClO2/AC catalysis-oxidation system was 10% higher than that of the system with only ClO2 when the COD concentration of paranitrobenzoic acid wastewater was 10 960 mg/L. It was also found that the COD removal was decreased by 35% with the concentration of 7 100 mg/L under the conditions of pH value 4.1, AC dosage 200 g/L, reaction time 30 min and ClO2 dosage 300 mg/L. In addition, the BOD, concentration was increased to 1 810 mg/L and the biodegradability was improved greatly with the BOD5/COD ratio increased from 0.10 to 0.25. In a word, the chlorine dioxide (ClO2) and activated carbon (AC) catalysis-oxidation process is an effective pretreatment method for paranitrobenzoic acid wastewater treatment.