One-dimensional inorganic high-k nanowires (NWs) show a potential of achieving high energy densities in polymer-matrix nanocomposite capacitors. In this study, we investigate a hydrothermal synthesis of BT NWs, by which BT NWs with high aspect ratios of pure phase, [110]-oriented structures were obtained. The BT NWs are filled in a polyvinylidene fluoride (PVDF) matrix to prepare nanocomposites and their dielectric and energy storage properties are investigated. An enhanced dielectric constant of epsilon(r) ~ 58 at 100 Hz is achieved in PVDF-BaTiO3 NWs (30 vol%), while the value is 47 for a traditional composite filled with BT nanoparticles (NPs). Besides, high breakdown strength of E-b > 362 MV/m is also achieved in the composites. PVDF-BaTiO3 NWs nanocomposite exhibits a high discharged energy density of U-d ~ 12.85 J/cm(3) at 300 MV/m at 100 Hz with a discharge efficiency of 58%. The simulation from the finite element analysis on distributions of voltage and electric displacement is studied and showed the consistency with experimental results. This study demonstrates a facile and large-scale route to the synthesis of BaTiO3 NWs for making high epsilon(r), E-b and U-d nanocomposite capacitors.