The polyimide (PI)/maghemite (-Fe2O3) nanocomposite fibers with magnetic behavior were prepared by electrospinning from polyamic acid/iron oxide (Fe3O4) solution, followed by thermal imidization process. The effect of Fe3O4 nanoparticles content in precursor mixture solution on the properties of PI/-Fe2O3 nanocomposite fibers was studied. The fibers were characterized using Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, and scanning electron microscopy. The magnetic and mechanical properties of the electrospun PI/-Fe2O3 nanocomposite fibers were also investigated. The study showed that magnetic nanoparticles existed in the nanofibers in the form of physical composite, and with the increasing Fe3O4 content, the nanocomposite fibers became thinner, the break strength and elongation at break of the fiber membranes slightly decreased, and the saturation magnetization increased.