Abstract: Solid polymer electrolyte films based on PMMA were prepared in different NaClO4 salt concentrations by solution cast technique. The features of complexion of these electrolytes were studied by X-ray diffraction (XRD). Film morphology was examined by Scanning Electron Microscopy (SEM). The electrical conductivity of pure and NaClO4 doped polymer electrolyte films was studied in the temperature range 303-393 K. The electrical conductivity increased with increasing dopant concentration and exhibited Arrhenius type dependent with temperature. The increase in conductivity with dopant concentration may be attributed to the formation of charge transfer complexes. Transport number data showed that the charge transport in this electrolyte system is predominately due to ions. Using this polymer electrolyte, solid state electro chemical cell have been fabricated, and their discharge profiles were studied under a constant load of 100 kΩ.