To study the effect of magnetic-responsive CNT/Fe 3 O 4 particles on the mechanical properties and proton conductivity of sulfonated poly(arylene ether nitrile) (SPEN) proton exchange membranes, a series of composite membranes consisting of magnetic carbon nanotube/iron oxide (CNT/Fe 3 O 4 ) hybrid particles and SPEN were successfully fabricated using a solution casting method, and their proton conductivity and thermal and mechanical properties were investigated. To explore the effect of the orientation of magnetic CNT/Fe 3 O 4 hybrid particles on proton exchange membranes, a magnetic field was applied beneath the casting membrane. Thermal analysis showed good thermal stability, with 5 % weight loss at temperatures in the range of 309 to 324 °C, and the mechanical properties of the composites were enhanced with increasing CNT/Fe 3 O 4 content. Proton conductivity increased as the content of [CNT/Fe 3 O 4 ] hybrid particle content regardless of the orientation or random distribution of CNTs, while the proton conductivity of SPENH membranes decreased slightly in the presence of a magnetic field. Therefore, we believe that these membranes would find potential applications as proton exchange membranes due to their enhanced mechanical strength and thermal stability.