Abstract: A custom plasma water treatment reactor generated non-thermal plasma via dielectric barrier discharge.Ferrous sulfatewere added to enhance plasma degradation of di-n-octyl phthalate （DOP） wastewater from the extraction process. Single-factor experiments evaluated the effects of discharge time, discharge voltage, ferrous sulfate catalyst concentration and flocculant concentration on DOP degradation. Response surface analysis used chemical oxygen demand （COD） removal rate as the main indicator;Total Organic Carbon （TOC） removal rate and turbidity removal rate as the secondary indicator. The response surface model predicted that under conditions of 40 kV discharge voltage, 120 min discharge time, 0.25 mol·L⁻¹ ferrous sulfate catalyst concentration, and 40 mg·L⁻¹ flocculant concentration, the COD;TOC and turbidity removal rates for DOP wastewater would be 93.81%, 83.35% and 97.70%, respectively; experimental verification yielded 93.50%, 83.12% and 96.80%, respectively. The active species quenching test confirmed that the degradation of DOP was mainly due to ·OH oxidation, Infrared and mass spectrometry validated the ferrous sulfate-assisted plasma method's effectiveness for DOP wastewater treatment. Provides a new reference for the degradation of DOP wastewater.