Abstract: In recent years, pharmaceutical emerging contaminants have been frequently detected in aquatic environments. As a typical antipyretic and analgesic drug, acetaminophen (ACE) has attracted increasing attention due to its high detection frequency and potential ecological concerns. To address the challenges of controlling such contaminants in water environments, a high-efficiency and stable catalytic system was constructed using ACE as the target pollutant. A manganese ferrite composite catalyst supported on carbon nanotubes (MnFe₂O₄@CNT) was synthesized via a one-step hydrothermal method, and its performance on the activation of peroxymonosulfate (PMS) for ACE degradation was systematically evaluated. The results showed that: (1) The MnFe₂O₄@CNT/PMS system exhibited excellent ACE removal efficiency, achieving 98% degradation within 25 min. (2) The quenching experiments and electron paramagnetic resonance (EPR) analysis revealed the synergistic involvement of both radical and non-radical pathways, with singlet oxygen (¹O₂) and superoxide radicals (O₂^•−) playing dominant roles. (3) The surface functional groups such as C=O and M—O (where M represents Mn and Fe), along with the Fe/Mn redox cycling, facilitated the continuous generation of reactive species. (4) The system exhibited excellent stability across a pH range of 3-11, magnetic separability, and resistance to interference from coexisting inorganic anions and other pollutants in complex water matrices. Overall, the MnFe₂O₄@CNT/PMS system enables efficient and wide-ranging removal of ACE, providing theoretical support for the rapid elimination of pharmaceutical emerging contaminants from aquatic environments.