<p>As the most used antibiotic in the world, ciprofloxacin （CIP） is considered an emerging pollutant due to its overuse. In this study, a new idea of CIP adsorption removal based on immobilized metal affinity is proposed. CIP was selected as the research object, metal ions were applied to modify cation exchange resins. IRC748–Cu(II) type adsorbent was screened. Characterizations and theoretical calculation of IRC748–Cu(II) were performed by SEM, XPS, FTIR, metal bonding amount and density functional theory. The effects of pH, time, temperature and interfering ions on the adsorption of CIP by IRC748–Cu(II) were investigated. At 10:1 amount ratio of the adsorbent and adsorbate, the adsorption capacity of IRC748–Cu(II) to CIP can reach 87.60 mg/g under 313 K with 200 rpm for 12 h, and the adsorption system has good anti-interference ability. The reusability experiment shows that IRC748–Cu(II) can still reach 84.82% of the initial adsorption capacity of CIP after 5 consecutive cycles of adsorption–desorption. LUMO, HOMO, surface electrostatic potential, adsorption energy and differential charge of IRC748–Cu(II) to CIP were calculated on the basis of density functional theory to reveal the potential removal mechanism between them. The calculations predict that the adsorption removal of IRC748–Cu(II) to CIP is based on the coordination interaction between Cu²⁺ and –NH– &amp; –COOH of CIP, and the coordination capacity of –NH– to Cu²⁺ is greater than that of –COOH.</p>