Recently, polyacrylonitrile (PAN) fiber films have shown greater advantages over polyvinylidene fluoride (PVDF) in the field of energy harvesting. Adding other substances with high piezoelectric coefficient is worth exploring to further improve the output voltage of PAN. Here, we successfully dispersed high dielectric constant barium titanate in PAN nanofiber films with different dosages using an electrospinning technology. The X-ray diffraction and Fourier transform infrared spectroscopy results indicated that BaTiO3 nanoparticles aid in transforming PAN from a 31-helical conformation to a planar zigzag conformation, thus improving the output voltage of PAN nanofibers significantly and also promoting its mechanical properties. In addition, the human body function monitoring experiment showed a good response current to the rhythm of elbow bending, knee bending, running, and breathing. Besides, when a simple rectifier circuit was applied, the capacitor could be charged to 2 V in less than 2 min and light a commercial LED through repeated tapping.