Thermoelectric (TE) films with excellent electrical transport property are integral for developing efficient in-plane heat dissipation technology, but low electrical transport property is a challenge that restricts their application. Recently, a thermo-electro-magnetic coupling novel effect is initiated to significantly enhance the comprehensive TE performance. To explore the influence of the above effect on the electron transport property of TE films, we developed an integration preparation method by ball milling dispersion, screen-printing and hot-pressing curing, obtaining a series of xFe/Bi _0.5Sb _1.5Te ₃(BST)/epoxy TE films where Fe nanoparticles severed as the second phase, from which the thermo-electro-magnetic coupling effect generated and the impact on the electrothermal transport performance was studied as a keystone. The results manifested that there was a coexistence of positive and negative magnetoresistance in xFe/BST/epoxy thermoelectromagnetic films; The preferred orientation factor of BST (000 l) was positively proportional to the positive magnetoresistance ( MR ⁺), resulting in an increase of the conductivity; The spin-dependent scattering of negative magnetoresistance ( MR ^-) derived from the local magnetic moment of strong ferromagnetic Fe nanoparticles boosted the Seebeck coefficient. Hence, the power factor of Fe/BST/epoxy thermoelectromagnetic film near room temperature reaches 2.87 mW K ^-2m ^-1, increased by 78% compared as that of BST/epoxy thermoelectric film. These results indicated that the coexistence of positive and negative magnetoresistance in thermoelectromagnetic films could not only de-couple the coupling relationship between conductivity and Seebeck coefficient in TE materials, but also provide a new physical mechanism for excellent TE conversion performance induced by magnetic nanoparticles.