Extracorporeal membrane oxygenation (ECMO) is one of the most important supporting therapies for patients with severe cardiopulmonary failure, and the core component of ECMO is the membrane oxygenator. However, in clinical application, the membrane oxygenator faces a dilemma in balancing anticoagulation and hemorrhage risks, which restrains the service life of membrane oxygenator and affects patients’ safety seriously. In this work, we introduce poly (1-vinyl-2-pyrrolidone) (PVP) and poly (acrylic acid) (PAA) into polyethersulfone (PES) membranes simply by in-situ crosslinking polymerization and nonsolvent induced phase separation (NIPS) method. All the modified membranes exhibit favorable hemocompatibility with prolonged activated partial thromboplastin time (APTT) (>10 s). Besides, the introduction of PAA can improve CO₂ and O₂ permeabilities simultaneously (increased by 36.57% and 30.86% at maximum, respectively, compared with pristine PES membrane). Finally, an ECMO-simulated gas-liquid contactor circulation device is designed, and the modified membranes show better oxygenation performance and CO₂ removal performance. The membrane modification and fabrication methods in this work are simple, low-cost, and easily industrialized. The work has practical guiding significance for the subsequent membrane research and application toward oxygenators.