The catalytic oxidation process combined with micro-nano bubbles is a new method to treat dye wastewater, which solves the problem of difficult biodegradable organic pollutants and reduces the chroma of dye wastewater, and has a good application prospect.Taking simulated cationic dye wastewater as the research object, with manganese nitrate/activated carbon (Mn/GAC) as the catalyst, the cationic dye wastewater was treated by ozone catalytic oxidation process combined with micro-nano bubbles aeration technology. Based on the determination of the initial concentration of cationic dye wastewater and ozone concentration, orthogonal tests of catalyst dosage, initial pH value of wastewater and initial wastewater temperature carried out, and their influence on the treatment effect of cationic gold X-GL dye wastewater was investigated. Experimental results show that catalytic oxidation of micro-nano bubbles can have a good effect on the chroma removal of cationic gold X-GL dye wastewater. When the amount of catalyst is 3.5 g/L, the initial pH is 9.4, and the initial temperature is 23.6 ℃, the verification experiment is carried out under this optimum combination condition, and the experimental results show that the best chroma removal rate is 95.6%. It shows that the treatment of dye wastewater by this process has achieved the expected effect and has a certain guiding significance.