The organic-inorganic nanocomposite films comprising poly(vinyl alcohol) (PVA) and poly(ethylene oxide) (PEO) blend matrix dispersed with alumina (Al2O3) nanoparticles (i.e., (PVA-PEO)-xwt% Al2O3; x = 0, 1, 3 or 5) have been prepared by the solution-cast method. The X-ray diffraction study confirms a large decrease in crystalline phase of the PVA-PEO blend structures with the addition of 1 wt% Al2O3, and it decreases gradually with the further increase of Al2O3 contents. Influence of Al2O3 nanofiller on the complex dielectric permittivity, electrical conductivity, electric modulus and the impedance properties of these polymer nanocomposite (PNC) films have been investigated over the frequency range from 20 Hz to 1 MHz by employing the dielectric relaxation spectroscopy (DRS). The ambient temperature dielectric permittivity values of the PNC films decrease initially up to 3 wt% Al2O3 loading in the PVA-PEO blend matrix, whereas for 5 wt% Al2O3, it again increases and exceeds the value of pristine polymer blend film. The relaxation processes exhibited in the dielectric loss tangent and the loss part of electric modulus spectra reveal that the polymers cooperative chain segmental motion enhances in the presence of Al2O3 nanoparticles in the PVA-PEO blend structures. Further, it has been found that the values of dielectric permittivity increase whereas the relaxation time decreases with the increase of temperature of the (PVA-PEO)-3 wt% Al2O3 film from 27 to 60 degrees C. The dielectric and electrical parameters of the PNC films have been analyzed in regards to their suitability as flexible-type novel nanodielectric material for the electrical insulation, the dielectric substrate in the fabrication of high performance organic microelectronic devices, and also in the preparation of nanocomposite solid polymer electrolytes (NSPEs) for the energy storing devices.