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In this study, BaTiO 3 nanofibers were synthesized by a two-step hydrothermal method and subsequently incorporated into poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) matrix to prepare nanocomposites for energy storage application. The crystalline phase, morphology and microstructure of BaTiO 3 nanofibers were observed by X-ray diffraction, scanning electron microscopy and transmission electron microscopy, respectively. The dielectric properties and energy storage performance of the nanocomposites were characterized by dielectric and ferroelectric analyzer. The BaTiO 3 nanofibers with tetragonal phase structure exhibited high aspect ratios, good dispersibility and compatibility in polymer matrix. The effects of volume fraction of BaTiO 3 nanofibers on the dielectric constant, breakdown strength and discharged energy density of the nanocomposites were investigated systematically. The dielectric constant of the BaTiO 3-P(VDF-HFP) nanocomposites remarkably improved with the increase of BaTiO 3 nanofiber contents at the same frequency. At 1 kHz, the maximum dielectric constant of the composite with 20vol% BaTiO 3 nanofibers is up to 30.69. The composite with 5vol% BaTiO 3 nanofibers achieves the maximum energy storage density (4.89 J/cm 3) and discharged energy density (2.58 J/cm 3) at 240 kV/mm.