A series of new polymer nanocomposites, ZnO(PEGME), in which ZnO nanoparticles and poly(ethylene glycol methyl ether) (PEGME) molecules are connected by covalent bonds, have been synthesized by a sol-gel route and purified by a non-solvent method. Various characterization techniques have been employed to determine the compositions and structures of the ZnO(PEGME)s, and their luminescent properties and ionic conductivities (after dissolving lithium salts to form solid polymer electrolytes) have been measured and compared with their counterparts-polymer nanocomposites prepared by mixing PEGME and ZnO nanoparticles physically. These comparisons prove that ZnO(PEGME) hybrids derived from chemical reactions have much better properties and stabilities than their counterparts. As a result, tunable photoluminescence of ZnO nanoparticles and stable conductivity of solid polymer electrolytes have been realized successfully.