Abstract: To address the challenge of severe membrane fouling induced by the co-existence of heavy metal ions and organic pollutants in hydraulic component electroplating wastewater, a coupled process system integrating modified resin adsorption pretreatment with ultrafiltration membrane separation was developed in this study. First, carboxylated D001 resin (MD001) was synthesized via surface grafting, with the successful introduction of carboxyl groups and changes in surface morphology validated by FT-IR and SEM. Taking MD001 resin and polysulfone (PSF) ultrafiltration membranes as research objects, the regulation mechanism of pretreatment on membrane fouling behavior was systematically investigated. Results demonstrated that MD001 resin exhibited superior adsorption capacity for Cu²⁺ at pH 5.0. In the coupled process, resin pretreatment effectively removed Cu²⁺ from the influent, weakening its bridging effect between organic matter and the membrane; consequently, the irreversible fouling rate decreased from 66% to 62%, the flux recovery rate increased from 32% to 37%, and the service life was extended. Meanwhile, this integrated process enhanced the oil rejection from 81% to 89% and improved the steady-state emulsion flux from 171 to 197 L·m^-2·h^-1. Ten-cycle stability tests further confirmed that the pretreatment system possesses more stable rejection performance and excellent anti-fouling resilience. The synergistic mechanism of “metal ion capture by resin and macromolecular organic rejection by membrane” revealed in this study provides a technical solution for treating complex electroplating wastewater that offers both high separation precision and long-term operational stability.