Solid polymer electrolytes have been extensively studied due to wide applications in various electrochemical devices [1]-[3]. Most of the solid polymer electrolytes consist of polymer as a host material to provide strength and good mechanical stability and an inorganic salt that supplies ionic carriers to cause electrical conductivity. In our studies, we prepared PVA/NH 4 NO 3 polymer electrolyte films by solution casting method. The prepared films with varied Ammonium Nitrate concentration from 0-20 wt% are characterized by XRD & FTIR spectroscopy. XRD results show that amorphous nature increases as the amount of the Ammonium Nitrate salt in PVA is increased. IR-spectra confirm the polymer salt complexes in the range of 3700-712 cm −1. Conductance analysis reveals that polymer electrolyte films containing 20 wt% of NH 4 NO 3 exhibit the highest ionic conductivity of 1.01 × 10 −7 S/cm while pure PVA films give the lowest ionic conductivity of 2.10 × 10 −11 S/cm. It was evident from this study that the increase of ionic conductivity depended on the Ammonium Nitrate salt concentration. The dielectric constant exponentially decreases with increase of frequency for pure PVA and NH 4 NO 3 doped PVA film composites. The temperature dependent studies of AC conductivity and dielectric constant also included to understand the conducting property. The results obtained by these studies are reported in this work.