Abstract: Degradation of bio-refractory crystal violet in simulated wastewater by ozone oxidation was experimentally studied. The reaction mechanism was discussed based on the analysis of ultraviolet spectroscopy, infrared spectroscopy, gas chromatography, chemical oxygen demand and total organic carbon. Results indicated that the removal rate of crystal violet could reach 97.0% under the optimum conditions, including initial crystal violet concentration of 0.88 mmol/L,ozone dosage of 9.06×10-5mol/min,reaction temperature of 25℃, pH of 10.0 and reaction time of 120 min. The detected intermediates of crystal violet oxidized by ozone are p-aminophenol, maleic acid, glyoxylic acid and other small organic molecules. The ultimate products are H2O and CO2.