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, Li+ transport number, and electrochemical potential window, have been systematically studied.