Network polymer electrolytes were prepared by photo-crosslinking reactions of three different polyether triacrylate oligomers in the presence of lithium salts. 2-(2-Methoxyethoxy)ethyl glycidyl ether was used as a new monomer for the preparation of network polyethers having short ether side chains. Network polyethers having no side chains were also prepared for comparison. A new salt, lithium bis(trifluoromethanesulfonyl)imide, and a conventional salt, lithium perchlorate, were complexed with the network polyethers. The effects of the network structures and the incorporated salt species on the electrochemical properties, including ionic conductivity, Lif transport number, and electrochemical potential window, have been systematically studied.