Cu-based catalyst prepared by impregnation method was used in the catalytic ozonation process. The influences of operating parameters on the treatment effect of secondary effluent in the industrial park was discussed. The three-dimensional emission electron microscope (3D-EEM) was used to analyze the variation characteristics of water quality. The result showed that when the reaction time of ozonation alone was 60 min, the removal rates of COD and total nitrogen (TN) were 29.7% and 5.3%, respectively, and SUVA254 indicating the degree of aromatization decreased rapidly from 2.7 L/(mg·m) to 1.0 L/(mg·m). When the dosage of Cu-based catalyst was 100 g/L and the reaction time was 60 min, the removal rates of COD and TN reached to 84.7% and 19.8%, respectively, and SUVA254 was stable at 0.9 L/(mg·m). The removal rate of total fluorescence intensity reached to 89.5% after catalytic ozonation reaction for 20 min.