With a view to enhancong the ionic conductivily via the control of chain mobility of solid polymer electrolyte (SPE) based. on poly(ether urethane) (PEU), polyurethane (PU) matrix containing polyethylene glycol (PEG) and polypropylene glycol (PPG) randomly distributed within matrix was synthesized from the simultaneous polymerization, of PEG-PU and PPG-PU prepolymers. The efficacy of PEG-co-PPG-PU complexed with LiClO4 salt as a SPE is discussed and compared with that of PEG-PU/LiClO4.