Poly(ethylene oxide) (PEG) 800 macromers (PE0800-MA) with different number of average functionalities (f) have been synthesized to copolymerize with unsaturated polyester having PEO 600 segments in macromolecular chains and LiClO4 to form graft polymer networks including both sample PEO grafts and star-like PEO side chains. The copolymerization between these two "monomers" went quite well. All these network systems were completely amorphous, and the ionic conductivities of the network were measured over a range of temperatures and found to increase with decreasing the f of PE0800-MA for same [EO unit]/[Li+] (= 50). For the lower f(f = 1.2) system, sigma = 3.8 x 10(-5) S cm(-1) at ambient temperature and for the higher f(f = 2.0) system, sigma = 1.4 x 10(-5) S cm(-1). The high ambient conductivities for these systems were attributed to more PEO grafts existed in the network. Another graft polymer network was also prepared with similar polyester, as mentioned above, but having PE0800 segments in the polyester chains and [EO unit]/[Li+] ratio of 30. It gave even higher conductivity of 4.4 x 10(-5) S Cm-1 at 298 K.