This paper aims to synthesize barium titanate (BaTiO3) nanocrystalline particles and to fabricate polyvinyl alcohol (PVA) films hosting BaTiO3 in order to enhance structural and optical properties. The tartrate precursor process is used to produce BaTiO3 nanocrystalline. By means of cast solution, the PVA – BaTiO3 nanocomposite films are prepared. The polymer films are described by X-ray diffractometer (XRD), Fourier-Transform Infrared (FTIR), UV–vis spectroscopy, and photoluminescence spectroscopy (PL). The study of XRD and FTIR indicates that complexity is established between BaTiO3 nanoparticles and PVA matrix. Furthermore, XRD analyzes emphasize a reduction in the crystallinity of polymer films by increasing of BaTiO3 nanoparticles within the matrix of PVA. It is noticed that as the BaTiO3 nanoparticles concentration increases in the PVA matrix, the optical band gap decreases while the Urbach energy increases. The PL spectra for PVA-BT films showed a photoemission peak at about 750 nm. This peak decreases in intensity and broadened with the increase of the BT concentration in the PVA matrix, which is related to the defects produced and causes disordering in the polymer matrix. The extinction coefficient, refractive index, optical conductivity and dielectric constants of the polymer films are also improved.