Barium ferrite micro/nano fibers were successfully prepared via the electrostatic spinning by using dimethyl formamide (DMF) as the solvent, and poly vinyl pyrrolidone (PVP) as the spinning auxiliaries. Effects of strontium substitution on the structure, morphology, and magnetic properties were investigated by scanning electron microscope (SEM), X-ray diffraction analysis (XRD), and vibration sample magnetometer (VSM). XRD patterns of the samples confirm that pure barium ferrite fibers form, and the Sr substitution makes the main peaks (110), (107), and (114) move to right slightly. Also, the FE-SEM images show that the Sr substituted fibers can keep complete fibrous morphology. Moreover, the VSM results demonstrate that the saturation magnetization can reach 56.7 emu/g when the fibers are calcined at 800 degrees C.