Abstract: To address the issues of low ozone mass transfer efficiency and unstable catalytic performance in traditional ozone-catalysis systems, a pilot-scale system integrating enhanced ozone dissolution with catalytic oxidation was developed and applied for the advanced treatment of secondary biologically treated pesticide wastewater from an industrial park in Jiangsu Province. Two operation modes, namely recirculation mode and series mode, were adopted. Comparative experiments against the conventional aeration diffuser mode were conducted, and key parameters such as hydraulic retention time and ozone dosage were optimized. Three-dimensional fluorescence spectroscopy and acute toxicity analysis were employed to evaluate the treatment performance and the changes in wastewater biological toxicity. The results showed that, compared with the conventional aeration diffuser mode, the recirculation mode increased the chemical oxygen demand (COD) removal efficiency from 11.5% to 44.4%, and the series mode increased it from 11.1% to 35.6%. Under the recirculation mode with a hydraulic retention time of 1 h and an ozone dosage of 62.5 mg/L, the system achieved the lowest treatment cost while satisfying the requirements of effluent COD below 55 mg/L and an O₃/ΔCOD ratio below 3. Under the series mode, with a hydraulic retention time of 1 h and an ozone dosage of 73 mg/L, the COD removal contributions of the dissolution stage and the catalytic reactor stage were 50%, indicating that the coupled system achieved synergistic enhancement between oxidation occurring in the dissolution stage and that in the catalytic reactor stage, jointly contributing to the efficient removal of organic pollutants. Furthermore, the system significantly degraded recalcitrant organic substances such as fulvic-like acids and reduced the luminescent bacteria inhibition rate from 63% to 36%. By establishing this pilot-scale system, the treatment cost was reduced to 1 yuan per ton, achieving dual improvements in both advanced treatment efficiency and economic performance, thereby providing a basis for the promotion and application of this technology.