Solid polymer electrolyte films consisting of poly (vinylidene fluoride-cohexa fluoro propylene) (PVdF-HFP), poly (methylmethacrylate) (PMMA) with varying concentration of LiClO4 are prepared by solvent-casting technique. The structural elucidation, complex formation andmorphological properties are studied by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and Scanning electron microscopy (SEM). The temperature dependent ionic conductivity of the polymer films seems to obey WLF equation. The conductivities of PVdFÂHFP-PMMAÂLiClO4complexes are determined at different salt concentrations. The highest ionic conductivity of 1.659X 10-5 S cm-1 is obtained for 8 wt.% LiClO4 in the polymer complex at 302K. The thermal stability of the electrolyte is ascertained from Differential ScanningCalorimetry (DSC).