Research on magnesium battery has gained momentum in recent years due to its high stability and hazardous free nature. For such batteries solid polymer electrolyte films have been prepared using blend polymer technique with the polymers polyvinyl alcohol (PVA) & polyacrylonitrile (PAN) (92.5PVA:7.5PAN) and Mg(ClO4)2 of different molar mass percentage (m.m.%) as 0.05%,0.1%,0.15%,0.2%,0.25% and 0.3% by solution casting technique using DMF as solvent. The XRD results confirms that the incorporation of magnesium salt (Mg(ClO4)2) which reduces the crystallinity of blend polymer (92.5PVA:7.5PAN). FTIR has been carried out to study the complex formation between the blend polymer and salt. AC impedance spectroscopy has been used to examine the ionic conductivity and dielectric behaviour of the blend polymer electrolyte (BPE). The maximum ionic conductivity of 2.96 × 10− 4 S/cm has been observed for the sample 92.5PVA:7.5PAN:0.25 m.m.% Mg(ClO4)2 at room temperature for which the activation energy measured is minimum (0.21 eV). Electrochemical studies show that highest conducting BPE has the highest electrochemical stability. Transference number measurement confirms that the conducting species are Mg2 + ion. Primary magnesium battery has been constructed with maximum conducting electrolyte system and its discharge characteristics have been studied.